- Email: [email protected]
Examining the relationship between antihypertensive medication satisfaction and adherence in older patients
Accepted Manuscript Examining the Relationship between Antihypertensive Medication Satisfaction and Adherence in Older Patients Yazed Sulaiman Al-Ruthia, BSc Pharm, PharmD, PhD, Song Hee Hong, PhD, Carolyn Graff, RN, PhD, Mehmet Kocak, PhD, David Solomon, PharmD, Robert Nolly, Msc PII:
S1551-7411(16)30199-1
DOI:
10.1016/j.sapharm.2016.06.013
Reference:
RSAP 765
To appear in:
Research in Social & Administrative Pharmacy
Received Date: 3 March 2016 Revised Date:
27 June 2016
Accepted Date: 29 June 2016
Please cite this article as: Al-Ruthia YS, Hong SH, Graff C, Kocak M, Solomon D, Nolly R, Examining the Relationship between Antihypertensive Medication Satisfaction and Adherence in Older Patients, Research in Social & Administrative Pharmacy (2016), doi: 10.1016/j.sapharm.2016.06.013. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Examining the Relationship between Antihypertensive Medication Satisfaction and Adherence in Older Patients
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Yazed Sulaiman Al-Ruthia, BSc Pharm, PharmD, PhD,1 Song Hee Hong, PhD,2 Carolyn Graff, RN, PhD,3 Mehmet Kocak, PhD,4 David Solomon, PharmD,5 Robert Nolly, Msc6
Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh, Saudi
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Arabia; 2Pharmaceutical Economics, Policy, and Outcomes Research, College of Pharmacy,
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Seoul National University, Seoul, Korea; 3Department of Advanced Practice and Doctoral Studies, College of Nursing, University of Tennessee Health Science Center, Memphis, Tennessee, USA; 4Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee, USA; and 5Department of Clinical Pharmacy and 6Department of
Memphis, Tennessee, USA
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Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center,
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Funding support: The authors acknowledge financial support from the College of Pharmacy Research Center and the Deanship of Scientific Research, King Saud University (Riyadh, Saudi
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Arabia) and from the University of Tennessee Health Science Center (Memphis, TN, USA). Authors of this study have nothing to disclose concerning possible financial or personal relations with commercial entities that may have a direct or indirect interest in the subject matter of this study.
Sponsors’ Role: Sponsor had no role in the design, methods, subject recruitment, data collections, analysis, and preparation of this study.
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Corresponding author: Yazed Sulaiman H Al-Ruthia, College of Pharmacy, King Saud University, PO Box 2454, Riyadh 11451, Saudi Arabia
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Phone: +966114677483 Fax: +966114677480 E-mail: [email protected]
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Examining the Relationship between Antihypertensive Medication Satisfaction and
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Adherence in Older Patients
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ABSTRACT
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Background: The relationship between medication adherence and treatment satisfaction has
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been consistently positive, however, this relationship has not been examined among older adults
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with hypertension.
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Objectives: The aim of this study was to examine the relationship between medication
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adherence and treatment satisfaction among a sample of older adults with hypertension.
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Methods: This was a survey-based cross-sectional study in which seven community senior
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centers in the city of Memphis, Tennessee and its surrounding areas were visited. Individuals
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aged 60 years and older with self-reported hypertension who visited the community senior
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centers between August and December 2013 were asked to participate. The participants’
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satisfaction with their antihypertensive medications was assessed using a newly developed scale.
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The Short Form Health Survey (SF-12v2) was used to assess the health-related quality of life
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(HRQoL). The Primary Care Assessment Survey (PCAS) Communication scale was used to
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assess the satisfaction with health care provider communication. The Beliefs about Medicines
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Questionnaire (BMQ-General) was used to assess the participant beliefs about medications. The
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eight-item Morisky Medication Adherence Scale (MMAS-8) was used to assess adherence to
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antihypertensive medications. And the Single Item Literacy Screener (SILS) was used to assess
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health literacy. Multiple linear regression was conducted to examine the relationship between
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medication adherence and satisfaction with antihypertensive therapy controlling for multiple
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variables.
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Results: One hundred and ninety participants with hypertension were included in the study.
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Most participants were white, women, aged ≥70 years, taking ≥2 prescription medications and
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having ≥2 medical conditions. After adjusting for age, education, number of prescription
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medications, race, health literacy, sex, marital status, SF-12v2 Physical Component Summary
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(PCS-12) and Mental Component Summary (MCS-12), and PCAS-Communication scores, the
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overall satisfaction score of the antihypertensive medication regimen was positively and
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significantly associated with MMAS-8 sore (β = 0.262; 95% confidence interval, 0.007-0.517; P
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= .043).
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Conclusions: Treatment satisfaction was associated with higher medication adherence among
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older adults with hypertension.
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INTRODUCTION
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The prescribing of medication is the most common health care intervention and is the
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main course of treatment for most patients, particularly the elderly.1 Although most prescription
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medications are effective in treating health conditions such as hypertension and diabetes, almost
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50% of patients do not take their medications as prescribed.2,3 Patient adherence to the
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prescribers’ recommendations is a complex and individual psychobehavioral phenomenon.3,4
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According to the World Health Organization, adherence to long-term therapy is defined as “the
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extent to which a person’s behavior --- taking medications, following a diet, and/or executing
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lifestyle changes --- corresponds with agreed recommendations from a health care provider.”5
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However, medication adherence can also be defined as the degree to which patients’ or their
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caregivers’ medications administration behavior coincides with their health care providers’
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advice with regard to timing, dosage, and frequency of administration during the prescribed time
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window.6 Consequences of medication nonadherence include worsening of disease, increased
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comorbid diseases, increased health care costs, and death.7,8 This is particularly true among
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hypertensive patients who do not adhere to prescribed antihypertensive medication regimens.9
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Medication nonadherence is prevalent among multiple patient populations; however, it is
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an increasing problem among older adults.10 The multitude of factors that may influence older
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adults’ adherence to their prescribed medication regimens are variable and can be
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sociodemographic (age, race, sex, and education), medical (comorbidities, number of
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medications, and treatment of adverse events), psychobehavioral (beliefs about medicine,
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understanding of the medical condition, and satisfaction with treatment), or economic (type of
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insurance, copayments, and coinsurance).10,11 Furthermore, declining cognitive abilities,
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dexterity problems, and poor health care provider-patient communications are additional factors
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that can lead to nonadherence and are common among older adults.12 Thus, older adults are at
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higher risk of adverse drug events, medication mismanagement, and poor health outcomes.13 For
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example, it was estimated that > 10% of unplanned admissions among older adults were related
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to adverse drug events.14 Therefore, health care researchers have examined the effects of
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multiple factors on patient adherence to prescribed medications such as culture, social support,
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medical status, age, gender, and cost of medications.15
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According to the latest report published by the Centers for Disease Control and
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Prevention, the prevalence of hypertension among older adults who are between 65 and 74 years
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old is about 65% and about 75% among those over 75 years old.16 Hypertension often represents
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a treatment dilemma to health care providers because of the multiple physiologic and behavioral
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factors that affect patient adherence to treatment plans.17 Therefore, addressing nonadherence to
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antihypertensive medications among older adults is imperative.
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Effective strategies for the treatment of hypertension among older adults should include a
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good understanding of the barriers to medication adherence.18 Patient-related characteristics such
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as health literacy, health beliefs, and satisfaction with health care are potentially modifiable
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factors that may influence patient adherence to medication.19 In addition, health care provider-
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patient communication can significantly affect patient adherence to medication.20 Older adults
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revere their health care providers and want to spend quality time with them to better understand
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their health conditions and verbalize their concerns.21 Therefore, nonadherence to health care
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provider advice and prescribed treatment by older adults can be greatly reduced by providing
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patient-centered care (eg, attentive listening, avoiding distractions, and engaging patients in
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decision-making).20,22 Medication beliefs may strongly predict medication adherence.23 These
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beliefs are dynamically changing and are potentially formed from the patients’ past experiences,
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sex, income, medical condition, health care delivery system, culture, and religion.23,24
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Furthermore, medication beliefs are considered by some health sociologists as hidden
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determinants of any treatment outcome.25 Therefore, different interventions to influence patient
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beliefs about medications, which are considered critical predictors of medication adherence, have
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been developed.26 Health-related quality of life has also been associated with medication
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adherence. Older adults with hypertension and poor health-related quality of life scores have
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reported low adherence levels to antihypertensive medications.27 Treatment satisfaction is
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another important factor that can affect patient adherence to prescribed medications.28 However,
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few studies have examined the effects of medication satisfaction on medication adherence.29,30
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Barbosa et al. conducted a literature review of published research articles that examined
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the association between treatment satisfaction and adherence between 2005 and 2010.29 All of
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the reviewed articles that met the inclusion criteria showed a positive association between
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treatment satisfaction and adherence.29 Moreover, Zyoud et al. conducted a study to examine the
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association between treatment satisfaction and medication adherence among a sample of
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hypertensive patients.30 Patients with low treatment satisfaction were more likely to be non-
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adherent to their antihypertensive medication regimens.30 Although there was a positive
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relationship between treatment satisfaction and adherence among older adults with anxiety
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disorders undergoing primary care psychology program,31 this relationship was not studied
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among older adults with hypertension (eg, ≥60 years).
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In this study, the aim was to examine the relation between older adults’ satisfaction with
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their antihypertensive medication regimens using a newly developed scale that assessed 5
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different attributes of medication (eg, effectiveness, adverse effects, ease of use, cost, and food
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interactions) and medication adherence, controlling for modifiable (eg, satisfaction with health
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care provider communication, and health-related quality of life) and nonmodifiable (eg, age,
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race, comorbidities) patient-related characteristics.
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METHODS
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Population This was a multicenter, cross-sectional survey study involving older adults ≥ 60 years old
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with self-reported hypertension. The study involved a convenience sampling technique, with
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older adults recruited between August and December 2013 from 7 community senior centers
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(Memphis, TN, USA, and surrounding areas). The minimum sample size necessary for a medium
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effect size at power 0.8 and α of 0.05 for a multiple linear regression analysis that included 13
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measured variables was 131 participants.32 Therefore, a sample of 300 participants was selected
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to ensure adequate statistical power.
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Data Collection
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Coordinators at community senior centers notified older adults about the study at least 1
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week before the scheduled start of data collection, and a pharmacist and research assistant
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explained the study to the participants. Data were collected using a set of questionnaires. Six
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main categories of variables were used: (1) sociodemographic and disease-related characteristics
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(eg, comorbidities and number of prescription medications), (2) adherence to antihypertensive
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medications, (3) antihypertensive medication satisfaction, (4) beliefs about medications, (5)
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health-related quality of life, and (6) satisfaction with health care provider communication. All
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participants gave their informed consent and received $20 grocery gift cards after completing the
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survey. The study was approved by the Institutional Review Board of the University of
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Tennessee Health Science Center.
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Sociodemographic and Disease-Related Characteristics Participants were asked to report their age, education, sex, marital status, race, and
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number of prescription medications taken daily. Participant’s level of health literacy was also
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assessed using the Single Item Literacy Screener.33 Participants also were asked to identify their
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medical conditions from a list of > 14 medical conditions prevalent in the general US population,
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particularly those for older adults.34
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Assessment of Medication Adherence
Medication adherence was assessed using Morisky Medication Adherence Scale
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(MMAS-8). The MMAS-8 is a validated self-reporting questionnaire consisting of 8 questions.35
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The MMAS-8 questions were phrased in a way to avoid the “yes-saying” bias, which is the
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patients’ tendency to give positive answers to health care providers.35 The questions address
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patient medication-taking behavior but not medication adherence determinants; it requires a
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dichotomous response (yes/no) to 7 of 8 questions, with 5-point Likert response scale for the last
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question.35 The level of adherence on the MMAS-8 has been found to be significantly associated
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with blood pressure control and pharmacy fill rates for antihypertensive medications.35
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According to the published scoring system of MMAS-8, scores can range from 0 to 8, with
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scores of < 6, 6 to < 8, and 8 reflecting low, medium, and high adherence, respectively.35
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Permission to use the MMAS-8 was approved by Professor Morisky through E-mail
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communications.
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Assessment of Antihypertensive Medication Satisfaction Satisfaction with antihypertensive medications was assessed by asking participants with
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hypertension to write down the names of their antihypertensive medications and rate each one of
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them on a 5-point Likert scale (with 1 as low and 5 as high), where a high rating score indicates
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high satisfaction with antihypertensive medications. Six medication attributes were included in
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this newly developed scale based on previously published literature (effectiveness, adverse
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effects, cost, ease of use, food interactions, and overall satisfaction with treatment).36-39
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Effectiveness, adverse or side effects, and convenience as well as overall satisfaction with
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treatment are four medication attributes that are part of the Treatment Satisfaction Questionnaire
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for Medication (TSQM).36 The cost of medication is another important medication attribute from
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the patient perspective that was reported in the literature.37,39 Furthermore, literature has shown
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that patients value the information they receive from the pharmacists regarding drug-food
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interactions,40 which are common among antihypertensive medications.38 Because older adults
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with hypertension may take multiple medications to control their disease, space for 4 different
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antihypertensive medications was provided. If the participant reported taking more than one
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antihypertensive medication, the average rating score of each of the medication attributes
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(effectiveness, adverse effects, cost, ease of use, food interaction, and overall rating) was taken.
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In addition, the average rating scores for antihypertensive medications that were rated by ≥ 10
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participants were provided to compare the satisfaction ratings of different antihypertensive
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medications. The internal consistency and validity of the antihypertensive medication rating
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scale were ensured in this study (Cronbach α was 0.82).
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Assessment of Beliefs About Medicines Beliefs about medications were assessed using the general section of the Beliefs About
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Medicines Questionnaire (BMQ-General). The BMQ has been validated across multiple health
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conditions.41,42 The general section includes 8 statements that were categorized into 2 themes: (1)
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BMQ-Harm, which includes beliefs about the intrinsic nature of medications and the extent to
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which they are perceived as harmful, and (2) BMQ-Overuse, which includes beliefs about the
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way medications are used and whether they are overprescribed.41 Each subscale (eg, BMQ-Harm
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and BMQ-Overuse) consists of 4 items that are scored using a 5-point Likert scale, with higher
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scores indicating stronger beliefs about the corresponding concepts in each subscale (eg, more
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negative beliefs about medicines). The scores for each subscale can range from 4 to 20.41
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Permission to reproduce and use the BMQ questionnaire was obtained from Professor Robert
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Horne (School of Pharmacy, University of London, London, UK).
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Assessment of Health-Related Quality of Life
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Health-related quality of life was assessed using the Short Form 12 version 2 health
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survey. The Short Form 12 version 2 health survey is a multipurpose, abridged form of the Short
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Form 36. It includes 12 items and yields 8 scale scores (eg, physical functioning, physical role,
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bodily pain, general health, vitality, social functioning, emotional role, and mental health).43 It
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was used to assess limitations in daily activity because of physical and mental health during the
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previous 4 weeks. It had 2 component summary scales, Physical Component Summary (PCS-12)
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and Mental Component Summary (MCS-12), with higher scores (range, 0-100) indicating better
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health-related quality of life.43 Permission to reproduce and use the Short Form 12 was obtained
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from the owner (QualityMetric Incorporated, Lincoln, RI, USA).
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Assessment of Satisfaction with Health Care Provider Communication Satisfaction with health care provider communication was assessed using the Primary
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Care Assessment Survey (PCAS) communication scale. The PCAS-Communication scale is 1 of
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11 PCAS scales designed to operationalize the formal definitions of primary care.44 These scales
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perform consistently well across diverse populations, with scores ranging from 0 to 100 and
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higher scores indicating more of the underlying attribute.44 The PCAS-Communication scale
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assessed participants’ satisfaction with their health care providers’ communication in terms of (1)
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thoroughness of questions being asked about symptoms, (2) attention to what participants say,
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(3) explanations provided about medical conditions and treatment, (4) instructions about
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symptoms to report and when to seek help, (5) advice and help in making decisions about care,
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and (6) whether unanswered questions remained after leaving the health care provider’s office.44
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Permission to reproduce and use the PCAS-Communications scale was obtained from the
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developer (Health Institute, Tufts-New England Medical Center, Boston, MA, USA).
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Statistical Analyses
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A Pearson correlation coefficient was used to identify the relation between the different
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rated attributes of antihypertensive medication and the relation between each of these rated
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attributes and MMAS-8, PCS-12 and MCS-12, PCAS-Communication, and BMQ-General
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scores. Multiple linear regression analyses were used to evaluate the correlation between
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MMAS-8 score and the participant-specific overall rating score of the antihypertensive
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medication regimen controlling for participant scores of PCS-12, MCS-12, PCAS-
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Communication, and comorbidities, number of prescription medications, health literacy, sex,
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age, race, marital status, and education. Descriptive statistics were used to describe the
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sociodemographic and disease-related characteristics of the hypertensive participants. Statistical
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significance was determined at an α of .05. All statistical analyses were performed using SAS
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version 9.4 (SAS Institute, Inc., Cary, NC, USA).
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RESULTS
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Among the 300 participants who were surveyed, 218 reported having hypertension and
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taking antihypertensive medications; however, 28 questionnaires were excluded because of
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missing data, resulting in 190 questionnaires with complete data included in the data analyses.
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Most participants were ≥ 70 years old, women, white, and not married, had a college or a
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postgraduate degree and good health literacy, reported using ≥ 2 prescription medications daily,
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and had ≥ 2 medical conditions (Table 1). The most prevalent medical conditions were
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rheumatoid arthritis (60.0%), type 2 diabetes mellitus (33.7%), and chronic back pain or sciatica
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(23.7%) (Table 2). Over one-half of the participants had high (50.5%), 28.4% had medium, and
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21.1% had low antihypertensive medication adherence.
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The mean scores of both the PCS-12 and MCS-12 were significantly higher among
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participants who had high adherence than among those with medium or low adherence (P = .048
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for PCS-12 and P = .004 for MCS-12). Furthermore, the mean PCAS-Communication score was
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significantly higher among participants with high adherence than among those with medium or
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low adherence (P = .048). However, the mean scores of both BMQ-Overuse and BMQ-Harm
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were not significantly different between the 3 adherence groups (P = .167 for BMQ-Overuse and
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P = .323 for BMQ-Harm) (Table 3).
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The mean antihypertensive medication regimen rating scores in the effectiveness, adverse
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effects, ease of use, cost, food interaction, and overall use were 4.40 ± 0.91, 3.33 ± 1.67, 4.51 ±
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0.95, 4.04 ± 1.29, 3.93 ± 1.47, and 4.49 ± 0.86. For antihypertensive medications rated by 10 or
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more participants (atenolol, amlodipine, hydrochlorothiazide, lisinopril, losartan, metoprolol, and
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valsartan), all had high rating scores in all of the included medication attributes, which indicate
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high participants’ satisfaction with these antihypertensive medications (Table 4). The total
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correlation between the overall use rating score and the other rating scores regarding
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antihypertensive medication (effectiveness, cost, adverse effects, ease of use, and food
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interaction) was strong and significant (r = 0.669; P < .001). Likewise, the total correlations
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between the rating scores of effectiveness (r = 0.603; P < .001), cost (r = 0.610; P < .001),
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adverse effects (r = 0.405; P < .001), ease of use (r = 0.649; P < .001), and food interactions (r =
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0.575; P < .001) were also significant. Furthermore, the overall use rating score was significantly
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correlated with the scores of both PCAS-Communication (r = 0.280; P = .001) and BMQ-Harm
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(r = -0.184; P = .012).
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In this study, because there were intercorrelations between the different ratings scores
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regarding antihypertensive medication use, the overall use rating score was included in the
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multiple linear regression model, whereas other aspects were excluded.45 After adjusting for age,
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education, number of prescription medication, race, health literacy, sex, marital status, and PCS-
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12, MCS-12, and PCAS-Communication scores, the overall rating score of the antihypertensive
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medication regimen was positively and significantly associated with MMAS-8 score (β = 0.262;
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95% confidence interval, 0.007-0.517; P = .043) (Table 5). Furthermore, the PCS-12 (β = 0.028;
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95% confidence interval, 0.007-0.049; P = .007), MCS-12 (β = 0.023; 95% confidence interval,
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0.0003-0.047; P = .046), and PCAS-Communication (β = 0.015; 95% confidence interval, 0.004-
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0.026; P = .008) scores were also positively and significantly associated with the MMAS-8 score
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(Table 6). Finally, age was also positively and significantly associated with the MMAS-8 score
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(β = 0.023; 95% confidence interval, 0.0003-0.047; P = .046) (Table 5).
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DISCUSSION
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Poor medication adherence is a major issue for the treatment of hypertension.2,3 Although
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it is considered one of the major causes of treatment failure, poor adherence remains hard to
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detect in clinical practice.3,4 Furthermore, it is still unclear what strategies are most effective in
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managing this phenomenon among geriatric patients.2,6 Therefore, exploring and identifying
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potentially modifiable factors that are linked to poor adherence among hypertensive geriatric
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patients is essential.18,19 Treatment satisfaction is 1 potentially modifiable factor believed to be
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correlated with medication adherence.28 In this study, the relation between medication adherence
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and satisfaction with antihypertensive medication regimens in older patients was examined,
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controlling for multiple medication adherence determinants.
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With the use of a brief and newly developed scale, the overall satisfaction with
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antihypertensive medications by older adults was significantly associated with medication
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adherence. The higher the overall satisfaction (higher overall rating scores), the more likely older
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adults adhered to their antihypertensive medication regimen (higher MMAS-8 score).
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Furthermore, the overall rating of antihypertensive medications by older adults was correlated
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with satisfaction with health care providers’ communication. Older adults who were satisfied
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with the communication from the health care providers (higher PCAS-Communication score)
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were more likely to be highly satisfied their antihypertensive medications. In addition, older
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adults who were highly satisfied with their antihypertensive medications were less likely to
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believe that prescription medications are inherently harmful (lower BMQ-Harm score).
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In addition to treatment satisfaction, medication adherence was significantly associated
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with the older adults’ health-related quality of life, satisfaction with health care providers’
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communication, and age. The higher the quality of life of the older adults (higher PCS-12 and
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MCS-12 scores), the more likely they adhered to their antihypertensive medications (higher
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MMAS-8 score). Likewise, the higher the satisfaction of the older adults with their health care
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providers’ communication (higher PCAS-Communication score), the more likely they had high
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medication adherence (higher MMAS-8 score). Interestingly, the higher the age of the older
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adults the more likely they adhered to their antihypertensive medications (higher MMAS-8
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score).
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The treatment satisfaction with antihypertensive medications that were rated by at least
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10 participants were provided to see if certain antihypertensive medications are more favorably
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viewed by older adults with hypertension than others. Although, there was not a significant
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difference in the ratings of the 7 antihypertensive medications that were rated by ≥ 10
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participants (atenolol, amlodipine, hydrochlorothiazide, lisinopril, losartan, valsartan, and
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metoprolol), given the small sample size, participants rated them differently. For example,
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amlodipine and lisinopril were rated high overall and were comparable to the other
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antihypertensive medications; however, ratings regarding their adverse effects were the lowest.
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This could be attributable to the higher likelihood of drug-induced throat irritation and cough and
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angioedema, particularly among African Americans who used lisinopril.46 Furthermore, the
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incidence of dizziness and ankle edema with amlodipine is higher among older adults with
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hypertension than in younger patients.47 Another example is with hydrochlorothiazide, which
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had the highest cost rating compared with the other antihypertensive medications that were rated
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by ≥ 10 participants. This could be because hydrochlorothiazide and other diuretics had the
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lowest out of pocket expense per Medicare beneficiary with hypertension per year, according to
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the US Agency for Healthcare Research and Quality.48
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The findings of this study are consistent with the literature. Treatment satisfaction was
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associated with higher medication adherence.28-30 Patients with hypertension who were highly
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satisfied with their antihypertensive medications were more likely to be adherent to their
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medications than their counterparts who were unsatisfied with their medications.30 Furthermore,
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satisfaction with health care providers’ communication was associated with higher treatment
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satisfaction and medication adherence.18,20,22 In addition, poor health-related quality of life was
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associated with lower medication adherence.27 Beliefs about medication are also considered one
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of the well-known predictors of medication adherence.23,42 Although, older age was associated
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with higher likelihood of poor medication adherence, some studies have shown the opposite.49,50
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However, what makes this study unique is that multiple confounders were controlled for that
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have not been controlled for in previous studies. The effects of treatment satisfaction on
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medication adherence was also evaluated among a sample of geriatric population with
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hypertension, which has not been examined before to the best of our knowledge.28
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Implications
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The results of this study have several practical implications. Older adults with high
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satisfaction regarding their hypertension treatment are more likely be satisfied with their health
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care provider’s communication, have positive beliefs about medications, and have higher
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medication adherence. Therefore, poor treatment satisfaction can be addressed by providing
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patient-centered communication, discussing patient beliefs about medications and refuting any
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baseless negative ones, and engaging patients in their health care decisions. These are likely to
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be effective strategies to overcoming the barrier to medication adherence among geriatric
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patients.18,20
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Limitations This was a cross-sectional study in which participants’ satisfaction with antihypertensive
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medications was assessed using a newly developed tool not previously validated, yet it achieved
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a high internal consistency reliability (α = 0.82). Therefore, the findings of this study cannot be
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generalized to other patient populations. Furthermore, the likelihood of recall bias with respect to
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the number of prescription medications, name of antihypertensive medications, and past medical
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history is high.51 This survey also consisted of multiple validated questionnaires that required at
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least 25 minutes to complete. Hence, it placed a significant cognitive burden on the respondents,
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particularly with this mode of administration in which the respondent has to read, comprehend,
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recall, and then answer the requested information.51,52 Furthermore, the willingness of the
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respondents to disclose some information, which is believed to be sensitive from their own
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perspective, is a common limitation in survey research.53 Regarding the Beliefs About Medicines
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Questionnaire (BMQ) used to assess participants’ beliefs about medications, although research
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has confirmed a significant association between the general domain of the BMQ and medication
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adherence in general, the specific domain of the BMQ was not included.26,42 In addition, health
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literacy was assessed using a single screening question.33 Although, this single health literacy
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screening question has been validated using both the Test of Functional Health Literacy in
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Adults and the Rapid Estimate of Adult Literacy in Medicine as reference standards, it is not as
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accurate as these 2 standard tests of health literacy.33 Finally, all of the participants were
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recruited from community senior centers and most of them were white, females, and were under
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70 years of age. This may limit the generalizability of the study.
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Conclusions Treatment satisfaction with antihypertensive medications was associated with high
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medication adherence among older adults, controlling for myriad of covariates. Therefore, low
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treatment satisfaction may be an important barrier to medication adherence among geriatric
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patients. Future research may benefit from including the Health Belief Model as a framework to
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identify appropriate interventions to improve treatment satisfaction among the geriatric
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population and eventually their adherence to treatment.
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ACKNOWLEDGEMENTS
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We thank Professors Donald Morisky and Robert Horne for granting permission to use the
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Morisky Medication Adherence Scale and the Beliefs About Medicines Questionnaire.
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Conflict of Interest: The authors had no conflict of interest to report.
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Authors’ Contributions: Study concept and design: Yazed Al-Ruthia, Song Hee Hong, and
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Robert Nolly, Mehmet Kocak. Acquisition of data: Yazed Al-Ruthia, Song Hee Hong. Analysis
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and interpretation of data: All authors. Preparation of manuscript: Yazed Al-Ruthia, Carolyn
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Graff, Song Hee Hong. Reviewing and revision: All authors.
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Sponsors’ Role: Sponsor had no role in the design, methods, subject recruitment, data
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collections, analysis, and preparation of this study.
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Tourangeau R. Cognitive sciences and survey methods. Building a bridge between disciplines,Washington, District of Columbia: National Academy Press. 1984:73-100. Bowling A. Mode of questionnaire administration can have serious effects on data quality. Journal of Public Health. 2005;27:281-291.
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Table 1. Baseline Characteristics of the Hypertensive Participants Characteristic Percent (%) Sex Male Female Ethnicity White African American Hispanic Other Education ≤ High school (1-12 years) Some college or college degree (13-16 years) Postgraduate degree (≥ 17 years) Age 60-70 years 71-80 years > 80 years Number of prescription medications 0-1 2-4 5-7 ≥8 Marital status Unmarried Married Health literacy Marginal/limited Good Number of other medical conditions 1 2-3 4-5 >5
Frequency (N = 190)
57.4 37.9 2.1 2.6
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43.2 43.7 13.2
43 147
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22.6 77.4
82 83 25
46.8 34.2 19.0
89 65 36
8.4 46.3 36.3 9.0
16 88 69 17
63.2 36.84
120 70
21.1 79.0
40 150
31.3 42.2 19.3 7.2
52 70 32 12
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Frequency 190 13 14 29 17 21 64 114 45 25 27 34 11 31
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Table 2. Self-Reported Chronic Health Conditions in the Hypertensive Sample Medical Condition Percent (%) Hypertension 100% Congestive heart failure 6.8 Myocardial infarction 7.4 Angina pectoris or coronary artery disease 15.3 Stroke 9.0 Pulmonary diseases (ie, asthma or chronic obstructive pulmonary 11.1 disease) Type 2 diabetes mellitus 33.7 Rheumatoid arthritis 60.0 Chronic back pain or sciatica 23.7 Depression 13.2 Gastroesophageal reflux disease or peptic ulcer 14.2 Cancer (other than skin cancer) 17.9 Sexual dysfunction 5.8 Irritable bowel syndrome or indigestion 16.3
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Table 3. Self-Reported Outcomes Across Adherence Levels Self-Reported Outcome
Low
Mean ± Standard Deviation Medium High
P Value
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Survey; PCS-12 = Physical Component Summary
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Quality of life PCS-12 44.26 ± 9.19 42.94 ± 10.31 47.02 ± 10.21 .048 MCS-12 49.01 ± 9.12 53.82 ± 10.30 54.85 ± 8.54 .004 Participants’ satisfaction with health care providers’ communication PCAS-Communication 64.75 ± 18.86 72.14 ± 16.97 77.13 ± 17.79 .048 Beliefs about medicines BMQ-Overuse 12.92 ± 2.84 12.90 ± 3.07 12.13 ± 2.64 .167 BMQ-Harm 9.45 ± 3.33 8.98 ± 2.78 8.63 ± 2.77 .323 BMQ = Beliefs About Medicines Questionnaire; MCS-12 = Mental Component Summary; PCAS = Primary Care Assessment
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Adverse Effect No. 9 34 12
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Table4. Antihypertensive Medication Rating (Medication Specific) (n = 148) Effectiveness Cost of Ease of Use Food Interaction Medication Medication Name No. Mean ± SD No. Mean ± SD No. Mean ± SD No. Mean ± SD Atenolol 14 4.58 ± 0.67 10 4.55 ± 0.70 10 4.36 ± 0.84 10 3.64 ± 1.66 Amlodipine 35 4.31 ± 0.72 34 4.41 ± 1.08 32 3.91 ± 1.30 33 3.88 ± 1.52 Hydrochlorothiazide 14 4.85 ± 0.29 12 4.92 ± 0.29 12 4.92 ± 0.29 12 4.85 ± 0.39
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Mean ± SD 3.40 ± 1.66 2.94 ± 1.86 4.08 ± 1.15
Overall No. 10 32 12
Mean ± SD 4.55 ± 0.70 4.50 ± 0.76 4.77 ± 0.39
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28 13 24 10
4.77 ± 0.65 5.00 ± 0.00 4.69 ± 0.87 4.88 ± 0.41
28 13 23 10
4.27 ± 1.12 4.50 ± 1.33 4.32 ± 0.99 4.56 ± 0.76
28 12 22 10
3.93 ± 1.52 4.15 ± 1.68 3.83 ± 1.69 4.14 ± 1.74
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4.56 ± 0.84 5.00 ± 0.00 4.76 ± 0.45 4.11 ± 0.82
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Lisinopril Losartan Metoprolol Valsartan SD= standard deviation.
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2.81 ± 1.80 3.86 ± 1.79 3.44 ± 1.78 3.14 ± 1.99
27 13 23 10
4.79 ± 0.40 4.71 ± 1.11 4.44 ± 0.99 4.38 ± 0.82
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Table 5. Multiple Linear Regression for the Association Between Medication Adherence (MMAS-8 Score) and Antihypertensive Medication Rating (Treatment Satisfaction) 95% Confidence Interval Variable β Estimate P Value 0.262 .043 0.007-0.517 Overall rating of antihypertensive medication 0.028
.007
MCS-12
0.023
.046
PCAS-Communication
0.015
.008
Age
0.050
.001
Comorbidity score
0.057
.363
-0.066-0.181
Number of prescription medications
0.036
.449
-0.059-0.133
Education
-0.051
.242
-0.138-0.035
-0.043
.795
-0.374-0.286
0.350
.180
-0.164-0.866
0.353
.158
-0.139-0.846
0.164
0.460
-0.273-0.602
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Race Health literacy Sex
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0.007-0.049
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PCS-12
0.0003-0.047 0.004-0.026 0.025-0.076
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MCS-12 = Mental Component Summary; MMAS-8 = Morisky Medication Adherence Scale; PCAS = Primary Care Assessment Survey; PCS-12 = Physical Component Summary
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Highlights Older adults’ satisfaction with their medications may influence their adherence.
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Older adults with poor health-related quality of life are more likely to have poor medication adherence.
Older adults who are satisfied with their health care providers’ communication are more
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likely to have high medication adherence,
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S1551-7411(16)30199-1
DOI:
10.1016/j.sapharm.2016.06.013
Reference:
RSAP 765
To appear in:
Research in Social & Administrative Pharmacy
Received Date: 3 March 2016 Revised Date:
27 June 2016
Accepted Date: 29 June 2016
Please cite this article as: Al-Ruthia YS, Hong SH, Graff C, Kocak M, Solomon D, Nolly R, Examining the Relationship between Antihypertensive Medication Satisfaction and Adherence in Older Patients, Research in Social & Administrative Pharmacy (2016), doi: 10.1016/j.sapharm.2016.06.013. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Examining the Relationship between Antihypertensive Medication Satisfaction and Adherence in Older Patients
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Yazed Sulaiman Al-Ruthia, BSc Pharm, PharmD, PhD,1 Song Hee Hong, PhD,2 Carolyn Graff, RN, PhD,3 Mehmet Kocak, PhD,4 David Solomon, PharmD,5 Robert Nolly, Msc6
Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh, Saudi
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Arabia; 2Pharmaceutical Economics, Policy, and Outcomes Research, College of Pharmacy,
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Seoul National University, Seoul, Korea; 3Department of Advanced Practice and Doctoral Studies, College of Nursing, University of Tennessee Health Science Center, Memphis, Tennessee, USA; 4Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee, USA; and 5Department of Clinical Pharmacy and 6Department of
Memphis, Tennessee, USA
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Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center,
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Funding support: The authors acknowledge financial support from the College of Pharmacy Research Center and the Deanship of Scientific Research, King Saud University (Riyadh, Saudi
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Arabia) and from the University of Tennessee Health Science Center (Memphis, TN, USA). Authors of this study have nothing to disclose concerning possible financial or personal relations with commercial entities that may have a direct or indirect interest in the subject matter of this study.
Sponsors’ Role: Sponsor had no role in the design, methods, subject recruitment, data collections, analysis, and preparation of this study.
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Corresponding author: Yazed Sulaiman H Al-Ruthia, College of Pharmacy, King Saud University, PO Box 2454, Riyadh 11451, Saudi Arabia
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Phone: +966114677483 Fax: +966114677480 E-mail: [email protected]
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Examining the Relationship between Antihypertensive Medication Satisfaction and
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Adherence in Older Patients
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ABSTRACT
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Background: The relationship between medication adherence and treatment satisfaction has
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been consistently positive, however, this relationship has not been examined among older adults
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with hypertension.
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Objectives: The aim of this study was to examine the relationship between medication
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adherence and treatment satisfaction among a sample of older adults with hypertension.
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Methods: This was a survey-based cross-sectional study in which seven community senior
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centers in the city of Memphis, Tennessee and its surrounding areas were visited. Individuals
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aged 60 years and older with self-reported hypertension who visited the community senior
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centers between August and December 2013 were asked to participate. The participants’
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satisfaction with their antihypertensive medications was assessed using a newly developed scale.
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The Short Form Health Survey (SF-12v2) was used to assess the health-related quality of life
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(HRQoL). The Primary Care Assessment Survey (PCAS) Communication scale was used to
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assess the satisfaction with health care provider communication. The Beliefs about Medicines
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Questionnaire (BMQ-General) was used to assess the participant beliefs about medications. The
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eight-item Morisky Medication Adherence Scale (MMAS-8) was used to assess adherence to
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antihypertensive medications. And the Single Item Literacy Screener (SILS) was used to assess
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health literacy. Multiple linear regression was conducted to examine the relationship between
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medication adherence and satisfaction with antihypertensive therapy controlling for multiple
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variables.
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Results: One hundred and ninety participants with hypertension were included in the study.
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Most participants were white, women, aged ≥70 years, taking ≥2 prescription medications and
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having ≥2 medical conditions. After adjusting for age, education, number of prescription
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medications, race, health literacy, sex, marital status, SF-12v2 Physical Component Summary
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(PCS-12) and Mental Component Summary (MCS-12), and PCAS-Communication scores, the
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overall satisfaction score of the antihypertensive medication regimen was positively and
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significantly associated with MMAS-8 sore (β = 0.262; 95% confidence interval, 0.007-0.517; P
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= .043).
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Conclusions: Treatment satisfaction was associated with higher medication adherence among
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older adults with hypertension.
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INTRODUCTION
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The prescribing of medication is the most common health care intervention and is the
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main course of treatment for most patients, particularly the elderly.1 Although most prescription
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medications are effective in treating health conditions such as hypertension and diabetes, almost
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50% of patients do not take their medications as prescribed.2,3 Patient adherence to the
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prescribers’ recommendations is a complex and individual psychobehavioral phenomenon.3,4
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According to the World Health Organization, adherence to long-term therapy is defined as “the
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extent to which a person’s behavior --- taking medications, following a diet, and/or executing
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lifestyle changes --- corresponds with agreed recommendations from a health care provider.”5
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However, medication adherence can also be defined as the degree to which patients’ or their
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caregivers’ medications administration behavior coincides with their health care providers’
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advice with regard to timing, dosage, and frequency of administration during the prescribed time
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window.6 Consequences of medication nonadherence include worsening of disease, increased
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comorbid diseases, increased health care costs, and death.7,8 This is particularly true among
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hypertensive patients who do not adhere to prescribed antihypertensive medication regimens.9
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Medication nonadherence is prevalent among multiple patient populations; however, it is
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an increasing problem among older adults.10 The multitude of factors that may influence older
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adults’ adherence to their prescribed medication regimens are variable and can be
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sociodemographic (age, race, sex, and education), medical (comorbidities, number of
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medications, and treatment of adverse events), psychobehavioral (beliefs about medicine,
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understanding of the medical condition, and satisfaction with treatment), or economic (type of
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insurance, copayments, and coinsurance).10,11 Furthermore, declining cognitive abilities,
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dexterity problems, and poor health care provider-patient communications are additional factors
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that can lead to nonadherence and are common among older adults.12 Thus, older adults are at
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higher risk of adverse drug events, medication mismanagement, and poor health outcomes.13 For
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example, it was estimated that > 10% of unplanned admissions among older adults were related
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to adverse drug events.14 Therefore, health care researchers have examined the effects of
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multiple factors on patient adherence to prescribed medications such as culture, social support,
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medical status, age, gender, and cost of medications.15
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According to the latest report published by the Centers for Disease Control and
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Prevention, the prevalence of hypertension among older adults who are between 65 and 74 years
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old is about 65% and about 75% among those over 75 years old.16 Hypertension often represents
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a treatment dilemma to health care providers because of the multiple physiologic and behavioral
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factors that affect patient adherence to treatment plans.17 Therefore, addressing nonadherence to
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antihypertensive medications among older adults is imperative.
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Effective strategies for the treatment of hypertension among older adults should include a
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good understanding of the barriers to medication adherence.18 Patient-related characteristics such
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as health literacy, health beliefs, and satisfaction with health care are potentially modifiable
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factors that may influence patient adherence to medication.19 In addition, health care provider-
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patient communication can significantly affect patient adherence to medication.20 Older adults
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revere their health care providers and want to spend quality time with them to better understand
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their health conditions and verbalize their concerns.21 Therefore, nonadherence to health care
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provider advice and prescribed treatment by older adults can be greatly reduced by providing
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patient-centered care (eg, attentive listening, avoiding distractions, and engaging patients in
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decision-making).20,22 Medication beliefs may strongly predict medication adherence.23 These
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beliefs are dynamically changing and are potentially formed from the patients’ past experiences,
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sex, income, medical condition, health care delivery system, culture, and religion.23,24
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Furthermore, medication beliefs are considered by some health sociologists as hidden
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determinants of any treatment outcome.25 Therefore, different interventions to influence patient
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beliefs about medications, which are considered critical predictors of medication adherence, have
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been developed.26 Health-related quality of life has also been associated with medication
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adherence. Older adults with hypertension and poor health-related quality of life scores have
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reported low adherence levels to antihypertensive medications.27 Treatment satisfaction is
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another important factor that can affect patient adherence to prescribed medications.28 However,
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few studies have examined the effects of medication satisfaction on medication adherence.29,30
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Barbosa et al. conducted a literature review of published research articles that examined
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the association between treatment satisfaction and adherence between 2005 and 2010.29 All of
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the reviewed articles that met the inclusion criteria showed a positive association between
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treatment satisfaction and adherence.29 Moreover, Zyoud et al. conducted a study to examine the
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association between treatment satisfaction and medication adherence among a sample of
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hypertensive patients.30 Patients with low treatment satisfaction were more likely to be non-
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adherent to their antihypertensive medication regimens.30 Although there was a positive
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relationship between treatment satisfaction and adherence among older adults with anxiety
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disorders undergoing primary care psychology program,31 this relationship was not studied
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among older adults with hypertension (eg, ≥60 years).
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In this study, the aim was to examine the relation between older adults’ satisfaction with
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their antihypertensive medication regimens using a newly developed scale that assessed 5
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different attributes of medication (eg, effectiveness, adverse effects, ease of use, cost, and food
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interactions) and medication adherence, controlling for modifiable (eg, satisfaction with health
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care provider communication, and health-related quality of life) and nonmodifiable (eg, age,
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race, comorbidities) patient-related characteristics.
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METHODS
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Population This was a multicenter, cross-sectional survey study involving older adults ≥ 60 years old
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with self-reported hypertension. The study involved a convenience sampling technique, with
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older adults recruited between August and December 2013 from 7 community senior centers
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(Memphis, TN, USA, and surrounding areas). The minimum sample size necessary for a medium
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effect size at power 0.8 and α of 0.05 for a multiple linear regression analysis that included 13
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measured variables was 131 participants.32 Therefore, a sample of 300 participants was selected
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to ensure adequate statistical power.
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Data Collection
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Coordinators at community senior centers notified older adults about the study at least 1
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week before the scheduled start of data collection, and a pharmacist and research assistant
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explained the study to the participants. Data were collected using a set of questionnaires. Six
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main categories of variables were used: (1) sociodemographic and disease-related characteristics
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(eg, comorbidities and number of prescription medications), (2) adherence to antihypertensive
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medications, (3) antihypertensive medication satisfaction, (4) beliefs about medications, (5)
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health-related quality of life, and (6) satisfaction with health care provider communication. All
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participants gave their informed consent and received $20 grocery gift cards after completing the
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survey. The study was approved by the Institutional Review Board of the University of
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Tennessee Health Science Center.
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Sociodemographic and Disease-Related Characteristics Participants were asked to report their age, education, sex, marital status, race, and
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number of prescription medications taken daily. Participant’s level of health literacy was also
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assessed using the Single Item Literacy Screener.33 Participants also were asked to identify their
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medical conditions from a list of > 14 medical conditions prevalent in the general US population,
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particularly those for older adults.34
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Assessment of Medication Adherence
Medication adherence was assessed using Morisky Medication Adherence Scale
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(MMAS-8). The MMAS-8 is a validated self-reporting questionnaire consisting of 8 questions.35
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The MMAS-8 questions were phrased in a way to avoid the “yes-saying” bias, which is the
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patients’ tendency to give positive answers to health care providers.35 The questions address
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patient medication-taking behavior but not medication adherence determinants; it requires a
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dichotomous response (yes/no) to 7 of 8 questions, with 5-point Likert response scale for the last
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question.35 The level of adherence on the MMAS-8 has been found to be significantly associated
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with blood pressure control and pharmacy fill rates for antihypertensive medications.35
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According to the published scoring system of MMAS-8, scores can range from 0 to 8, with
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scores of < 6, 6 to < 8, and 8 reflecting low, medium, and high adherence, respectively.35
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Permission to use the MMAS-8 was approved by Professor Morisky through E-mail
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communications.
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Assessment of Antihypertensive Medication Satisfaction Satisfaction with antihypertensive medications was assessed by asking participants with
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hypertension to write down the names of their antihypertensive medications and rate each one of
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them on a 5-point Likert scale (with 1 as low and 5 as high), where a high rating score indicates
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high satisfaction with antihypertensive medications. Six medication attributes were included in
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this newly developed scale based on previously published literature (effectiveness, adverse
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effects, cost, ease of use, food interactions, and overall satisfaction with treatment).36-39
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Effectiveness, adverse or side effects, and convenience as well as overall satisfaction with
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treatment are four medication attributes that are part of the Treatment Satisfaction Questionnaire
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for Medication (TSQM).36 The cost of medication is another important medication attribute from
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the patient perspective that was reported in the literature.37,39 Furthermore, literature has shown
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that patients value the information they receive from the pharmacists regarding drug-food
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interactions,40 which are common among antihypertensive medications.38 Because older adults
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with hypertension may take multiple medications to control their disease, space for 4 different
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antihypertensive medications was provided. If the participant reported taking more than one
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antihypertensive medication, the average rating score of each of the medication attributes
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(effectiveness, adverse effects, cost, ease of use, food interaction, and overall rating) was taken.
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In addition, the average rating scores for antihypertensive medications that were rated by ≥ 10
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participants were provided to compare the satisfaction ratings of different antihypertensive
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medications. The internal consistency and validity of the antihypertensive medication rating
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scale were ensured in this study (Cronbach α was 0.82).
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Assessment of Beliefs About Medicines Beliefs about medications were assessed using the general section of the Beliefs About
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Medicines Questionnaire (BMQ-General). The BMQ has been validated across multiple health
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conditions.41,42 The general section includes 8 statements that were categorized into 2 themes: (1)
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BMQ-Harm, which includes beliefs about the intrinsic nature of medications and the extent to
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which they are perceived as harmful, and (2) BMQ-Overuse, which includes beliefs about the
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way medications are used and whether they are overprescribed.41 Each subscale (eg, BMQ-Harm
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and BMQ-Overuse) consists of 4 items that are scored using a 5-point Likert scale, with higher
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scores indicating stronger beliefs about the corresponding concepts in each subscale (eg, more
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negative beliefs about medicines). The scores for each subscale can range from 4 to 20.41
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Permission to reproduce and use the BMQ questionnaire was obtained from Professor Robert
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Horne (School of Pharmacy, University of London, London, UK).
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Assessment of Health-Related Quality of Life
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Health-related quality of life was assessed using the Short Form 12 version 2 health
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survey. The Short Form 12 version 2 health survey is a multipurpose, abridged form of the Short
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Form 36. It includes 12 items and yields 8 scale scores (eg, physical functioning, physical role,
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bodily pain, general health, vitality, social functioning, emotional role, and mental health).43 It
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was used to assess limitations in daily activity because of physical and mental health during the
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previous 4 weeks. It had 2 component summary scales, Physical Component Summary (PCS-12)
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and Mental Component Summary (MCS-12), with higher scores (range, 0-100) indicating better
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health-related quality of life.43 Permission to reproduce and use the Short Form 12 was obtained
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from the owner (QualityMetric Incorporated, Lincoln, RI, USA).
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Assessment of Satisfaction with Health Care Provider Communication Satisfaction with health care provider communication was assessed using the Primary
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Care Assessment Survey (PCAS) communication scale. The PCAS-Communication scale is 1 of
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11 PCAS scales designed to operationalize the formal definitions of primary care.44 These scales
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perform consistently well across diverse populations, with scores ranging from 0 to 100 and
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higher scores indicating more of the underlying attribute.44 The PCAS-Communication scale
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assessed participants’ satisfaction with their health care providers’ communication in terms of (1)
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thoroughness of questions being asked about symptoms, (2) attention to what participants say,
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(3) explanations provided about medical conditions and treatment, (4) instructions about
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symptoms to report and when to seek help, (5) advice and help in making decisions about care,
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and (6) whether unanswered questions remained after leaving the health care provider’s office.44
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Permission to reproduce and use the PCAS-Communications scale was obtained from the
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developer (Health Institute, Tufts-New England Medical Center, Boston, MA, USA).
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Statistical Analyses
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A Pearson correlation coefficient was used to identify the relation between the different
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rated attributes of antihypertensive medication and the relation between each of these rated
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attributes and MMAS-8, PCS-12 and MCS-12, PCAS-Communication, and BMQ-General
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scores. Multiple linear regression analyses were used to evaluate the correlation between
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MMAS-8 score and the participant-specific overall rating score of the antihypertensive
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medication regimen controlling for participant scores of PCS-12, MCS-12, PCAS-
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Communication, and comorbidities, number of prescription medications, health literacy, sex,
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age, race, marital status, and education. Descriptive statistics were used to describe the
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sociodemographic and disease-related characteristics of the hypertensive participants. Statistical
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significance was determined at an α of .05. All statistical analyses were performed using SAS
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version 9.4 (SAS Institute, Inc., Cary, NC, USA).
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RESULTS
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Among the 300 participants who were surveyed, 218 reported having hypertension and
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taking antihypertensive medications; however, 28 questionnaires were excluded because of
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missing data, resulting in 190 questionnaires with complete data included in the data analyses.
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Most participants were ≥ 70 years old, women, white, and not married, had a college or a
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postgraduate degree and good health literacy, reported using ≥ 2 prescription medications daily,
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and had ≥ 2 medical conditions (Table 1). The most prevalent medical conditions were
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rheumatoid arthritis (60.0%), type 2 diabetes mellitus (33.7%), and chronic back pain or sciatica
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(23.7%) (Table 2). Over one-half of the participants had high (50.5%), 28.4% had medium, and
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21.1% had low antihypertensive medication adherence.
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The mean scores of both the PCS-12 and MCS-12 were significantly higher among
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participants who had high adherence than among those with medium or low adherence (P = .048
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for PCS-12 and P = .004 for MCS-12). Furthermore, the mean PCAS-Communication score was
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significantly higher among participants with high adherence than among those with medium or
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low adherence (P = .048). However, the mean scores of both BMQ-Overuse and BMQ-Harm
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were not significantly different between the 3 adherence groups (P = .167 for BMQ-Overuse and
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P = .323 for BMQ-Harm) (Table 3).
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The mean antihypertensive medication regimen rating scores in the effectiveness, adverse
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effects, ease of use, cost, food interaction, and overall use were 4.40 ± 0.91, 3.33 ± 1.67, 4.51 ±
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0.95, 4.04 ± 1.29, 3.93 ± 1.47, and 4.49 ± 0.86. For antihypertensive medications rated by 10 or
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more participants (atenolol, amlodipine, hydrochlorothiazide, lisinopril, losartan, metoprolol, and
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valsartan), all had high rating scores in all of the included medication attributes, which indicate
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high participants’ satisfaction with these antihypertensive medications (Table 4). The total
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correlation between the overall use rating score and the other rating scores regarding
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antihypertensive medication (effectiveness, cost, adverse effects, ease of use, and food
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interaction) was strong and significant (r = 0.669; P < .001). Likewise, the total correlations
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between the rating scores of effectiveness (r = 0.603; P < .001), cost (r = 0.610; P < .001),
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adverse effects (r = 0.405; P < .001), ease of use (r = 0.649; P < .001), and food interactions (r =
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0.575; P < .001) were also significant. Furthermore, the overall use rating score was significantly
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correlated with the scores of both PCAS-Communication (r = 0.280; P = .001) and BMQ-Harm
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(r = -0.184; P = .012).
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In this study, because there were intercorrelations between the different ratings scores
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regarding antihypertensive medication use, the overall use rating score was included in the
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multiple linear regression model, whereas other aspects were excluded.45 After adjusting for age,
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education, number of prescription medication, race, health literacy, sex, marital status, and PCS-
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12, MCS-12, and PCAS-Communication scores, the overall rating score of the antihypertensive
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medication regimen was positively and significantly associated with MMAS-8 score (β = 0.262;
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95% confidence interval, 0.007-0.517; P = .043) (Table 5). Furthermore, the PCS-12 (β = 0.028;
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95% confidence interval, 0.007-0.049; P = .007), MCS-12 (β = 0.023; 95% confidence interval,
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0.0003-0.047; P = .046), and PCAS-Communication (β = 0.015; 95% confidence interval, 0.004-
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0.026; P = .008) scores were also positively and significantly associated with the MMAS-8 score
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(Table 6). Finally, age was also positively and significantly associated with the MMAS-8 score
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(β = 0.023; 95% confidence interval, 0.0003-0.047; P = .046) (Table 5).
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DISCUSSION
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Poor medication adherence is a major issue for the treatment of hypertension.2,3 Although
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it is considered one of the major causes of treatment failure, poor adherence remains hard to
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detect in clinical practice.3,4 Furthermore, it is still unclear what strategies are most effective in
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managing this phenomenon among geriatric patients.2,6 Therefore, exploring and identifying
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potentially modifiable factors that are linked to poor adherence among hypertensive geriatric
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patients is essential.18,19 Treatment satisfaction is 1 potentially modifiable factor believed to be
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correlated with medication adherence.28 In this study, the relation between medication adherence
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and satisfaction with antihypertensive medication regimens in older patients was examined,
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controlling for multiple medication adherence determinants.
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With the use of a brief and newly developed scale, the overall satisfaction with
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antihypertensive medications by older adults was significantly associated with medication
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adherence. The higher the overall satisfaction (higher overall rating scores), the more likely older
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adults adhered to their antihypertensive medication regimen (higher MMAS-8 score).
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Furthermore, the overall rating of antihypertensive medications by older adults was correlated
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with satisfaction with health care providers’ communication. Older adults who were satisfied
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with the communication from the health care providers (higher PCAS-Communication score)
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were more likely to be highly satisfied their antihypertensive medications. In addition, older
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adults who were highly satisfied with their antihypertensive medications were less likely to
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believe that prescription medications are inherently harmful (lower BMQ-Harm score).
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In addition to treatment satisfaction, medication adherence was significantly associated
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with the older adults’ health-related quality of life, satisfaction with health care providers’
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communication, and age. The higher the quality of life of the older adults (higher PCS-12 and
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MCS-12 scores), the more likely they adhered to their antihypertensive medications (higher
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MMAS-8 score). Likewise, the higher the satisfaction of the older adults with their health care
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providers’ communication (higher PCAS-Communication score), the more likely they had high
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medication adherence (higher MMAS-8 score). Interestingly, the higher the age of the older
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adults the more likely they adhered to their antihypertensive medications (higher MMAS-8
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score).
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The treatment satisfaction with antihypertensive medications that were rated by at least
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10 participants were provided to see if certain antihypertensive medications are more favorably
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viewed by older adults with hypertension than others. Although, there was not a significant
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difference in the ratings of the 7 antihypertensive medications that were rated by ≥ 10
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participants (atenolol, amlodipine, hydrochlorothiazide, lisinopril, losartan, valsartan, and
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metoprolol), given the small sample size, participants rated them differently. For example,
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amlodipine and lisinopril were rated high overall and were comparable to the other
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antihypertensive medications; however, ratings regarding their adverse effects were the lowest.
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This could be attributable to the higher likelihood of drug-induced throat irritation and cough and
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angioedema, particularly among African Americans who used lisinopril.46 Furthermore, the
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incidence of dizziness and ankle edema with amlodipine is higher among older adults with
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hypertension than in younger patients.47 Another example is with hydrochlorothiazide, which
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had the highest cost rating compared with the other antihypertensive medications that were rated
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by ≥ 10 participants. This could be because hydrochlorothiazide and other diuretics had the
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lowest out of pocket expense per Medicare beneficiary with hypertension per year, according to
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the US Agency for Healthcare Research and Quality.48
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The findings of this study are consistent with the literature. Treatment satisfaction was
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associated with higher medication adherence.28-30 Patients with hypertension who were highly
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satisfied with their antihypertensive medications were more likely to be adherent to their
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medications than their counterparts who were unsatisfied with their medications.30 Furthermore,
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satisfaction with health care providers’ communication was associated with higher treatment
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satisfaction and medication adherence.18,20,22 In addition, poor health-related quality of life was
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associated with lower medication adherence.27 Beliefs about medication are also considered one
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of the well-known predictors of medication adherence.23,42 Although, older age was associated
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with higher likelihood of poor medication adherence, some studies have shown the opposite.49,50
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However, what makes this study unique is that multiple confounders were controlled for that
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have not been controlled for in previous studies. The effects of treatment satisfaction on
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medication adherence was also evaluated among a sample of geriatric population with
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hypertension, which has not been examined before to the best of our knowledge.28
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Implications
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The results of this study have several practical implications. Older adults with high
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satisfaction regarding their hypertension treatment are more likely be satisfied with their health
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care provider’s communication, have positive beliefs about medications, and have higher
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medication adherence. Therefore, poor treatment satisfaction can be addressed by providing
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patient-centered communication, discussing patient beliefs about medications and refuting any
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baseless negative ones, and engaging patients in their health care decisions. These are likely to
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be effective strategies to overcoming the barrier to medication adherence among geriatric
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patients.18,20
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Limitations This was a cross-sectional study in which participants’ satisfaction with antihypertensive
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medications was assessed using a newly developed tool not previously validated, yet it achieved
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a high internal consistency reliability (α = 0.82). Therefore, the findings of this study cannot be
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generalized to other patient populations. Furthermore, the likelihood of recall bias with respect to
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the number of prescription medications, name of antihypertensive medications, and past medical
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history is high.51 This survey also consisted of multiple validated questionnaires that required at
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least 25 minutes to complete. Hence, it placed a significant cognitive burden on the respondents,
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particularly with this mode of administration in which the respondent has to read, comprehend,
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recall, and then answer the requested information.51,52 Furthermore, the willingness of the
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respondents to disclose some information, which is believed to be sensitive from their own
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perspective, is a common limitation in survey research.53 Regarding the Beliefs About Medicines
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Questionnaire (BMQ) used to assess participants’ beliefs about medications, although research
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has confirmed a significant association between the general domain of the BMQ and medication
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adherence in general, the specific domain of the BMQ was not included.26,42 In addition, health
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literacy was assessed using a single screening question.33 Although, this single health literacy
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screening question has been validated using both the Test of Functional Health Literacy in
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Adults and the Rapid Estimate of Adult Literacy in Medicine as reference standards, it is not as
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accurate as these 2 standard tests of health literacy.33 Finally, all of the participants were
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recruited from community senior centers and most of them were white, females, and were under
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70 years of age. This may limit the generalizability of the study.
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Conclusions Treatment satisfaction with antihypertensive medications was associated with high
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medication adherence among older adults, controlling for myriad of covariates. Therefore, low
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treatment satisfaction may be an important barrier to medication adherence among geriatric
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patients. Future research may benefit from including the Health Belief Model as a framework to
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identify appropriate interventions to improve treatment satisfaction among the geriatric
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population and eventually their adherence to treatment.
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ACKNOWLEDGEMENTS
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We thank Professors Donald Morisky and Robert Horne for granting permission to use the
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Morisky Medication Adherence Scale and the Beliefs About Medicines Questionnaire.
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Conflict of Interest: The authors had no conflict of interest to report.
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Authors’ Contributions: Study concept and design: Yazed Al-Ruthia, Song Hee Hong, and
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Robert Nolly, Mehmet Kocak. Acquisition of data: Yazed Al-Ruthia, Song Hee Hong. Analysis
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and interpretation of data: All authors. Preparation of manuscript: Yazed Al-Ruthia, Carolyn
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Graff, Song Hee Hong. Reviewing and revision: All authors.
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Sponsors’ Role: Sponsor had no role in the design, methods, subject recruitment, data
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collections, analysis, and preparation of this study.
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Table 1. Baseline Characteristics of the Hypertensive Participants Characteristic Percent (%) Sex Male Female Ethnicity White African American Hispanic Other Education ≤ High school (1-12 years) Some college or college degree (13-16 years) Postgraduate degree (≥ 17 years) Age 60-70 years 71-80 years > 80 years Number of prescription medications 0-1 2-4 5-7 ≥8 Marital status Unmarried Married Health literacy Marginal/limited Good Number of other medical conditions 1 2-3 4-5 >5
Frequency (N = 190)
57.4 37.9 2.1 2.6
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43.2 43.7 13.2
43 147
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22.6 77.4
82 83 25
46.8 34.2 19.0
89 65 36
8.4 46.3 36.3 9.0
16 88 69 17
63.2 36.84
120 70
21.1 79.0
40 150
31.3 42.2 19.3 7.2
52 70 32 12
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Frequency 190 13 14 29 17 21 64 114 45 25 27 34 11 31
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Table 2. Self-Reported Chronic Health Conditions in the Hypertensive Sample Medical Condition Percent (%) Hypertension 100% Congestive heart failure 6.8 Myocardial infarction 7.4 Angina pectoris or coronary artery disease 15.3 Stroke 9.0 Pulmonary diseases (ie, asthma or chronic obstructive pulmonary 11.1 disease) Type 2 diabetes mellitus 33.7 Rheumatoid arthritis 60.0 Chronic back pain or sciatica 23.7 Depression 13.2 Gastroesophageal reflux disease or peptic ulcer 14.2 Cancer (other than skin cancer) 17.9 Sexual dysfunction 5.8 Irritable bowel syndrome or indigestion 16.3
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Table 3. Self-Reported Outcomes Across Adherence Levels Self-Reported Outcome
Low
Mean ± Standard Deviation Medium High
P Value
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Survey; PCS-12 = Physical Component Summary
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Quality of life PCS-12 44.26 ± 9.19 42.94 ± 10.31 47.02 ± 10.21 .048 MCS-12 49.01 ± 9.12 53.82 ± 10.30 54.85 ± 8.54 .004 Participants’ satisfaction with health care providers’ communication PCAS-Communication 64.75 ± 18.86 72.14 ± 16.97 77.13 ± 17.79 .048 Beliefs about medicines BMQ-Overuse 12.92 ± 2.84 12.90 ± 3.07 12.13 ± 2.64 .167 BMQ-Harm 9.45 ± 3.33 8.98 ± 2.78 8.63 ± 2.77 .323 BMQ = Beliefs About Medicines Questionnaire; MCS-12 = Mental Component Summary; PCAS = Primary Care Assessment
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Adverse Effect No. 9 34 12
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Table4. Antihypertensive Medication Rating (Medication Specific) (n = 148) Effectiveness Cost of Ease of Use Food Interaction Medication Medication Name No. Mean ± SD No. Mean ± SD No. Mean ± SD No. Mean ± SD Atenolol 14 4.58 ± 0.67 10 4.55 ± 0.70 10 4.36 ± 0.84 10 3.64 ± 1.66 Amlodipine 35 4.31 ± 0.72 34 4.41 ± 1.08 32 3.91 ± 1.30 33 3.88 ± 1.52 Hydrochlorothiazide 14 4.85 ± 0.29 12 4.92 ± 0.29 12 4.92 ± 0.29 12 4.85 ± 0.39
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Mean ± SD 3.40 ± 1.66 2.94 ± 1.86 4.08 ± 1.15
Overall No. 10 32 12
Mean ± SD 4.55 ± 0.70 4.50 ± 0.76 4.77 ± 0.39
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4.77 ± 0.65 5.00 ± 0.00 4.69 ± 0.87 4.88 ± 0.41
28 13 23 10
4.27 ± 1.12 4.50 ± 1.33 4.32 ± 0.99 4.56 ± 0.76
28 12 22 10
3.93 ± 1.52 4.15 ± 1.68 3.83 ± 1.69 4.14 ± 1.74
29 13 23 10
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4.56 ± 0.84 5.00 ± 0.00 4.76 ± 0.45 4.11 ± 0.82
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Lisinopril Losartan Metoprolol Valsartan SD= standard deviation.
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2.81 ± 1.80 3.86 ± 1.79 3.44 ± 1.78 3.14 ± 1.99
27 13 23 10
4.79 ± 0.40 4.71 ± 1.11 4.44 ± 0.99 4.38 ± 0.82
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Table 5. Multiple Linear Regression for the Association Between Medication Adherence (MMAS-8 Score) and Antihypertensive Medication Rating (Treatment Satisfaction) 95% Confidence Interval Variable β Estimate P Value 0.262 .043 0.007-0.517 Overall rating of antihypertensive medication 0.028
.007
MCS-12
0.023
.046
PCAS-Communication
0.015
.008
Age
0.050
.001
Comorbidity score
0.057
.363
-0.066-0.181
Number of prescription medications
0.036
.449
-0.059-0.133
Education
-0.051
.242
-0.138-0.035
-0.043
.795
-0.374-0.286
0.350
.180
-0.164-0.866
0.353
.158
-0.139-0.846
0.164
0.460
-0.273-0.602
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Race Health literacy Sex
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0.007-0.049
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PCS-12
0.0003-0.047 0.004-0.026 0.025-0.076
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Highlights Older adults’ satisfaction with their medications may influence their adherence.
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Older adults with poor health-related quality of life are more likely to have poor medication adherence.
Older adults who are satisfied with their health care providers’ communication are more
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