Factors associated with medication noncompliance in rural elderly hypertensive patients

AJH 1995; 8:206-209

Factors Associated With Medication Noncompliance in Rural Elderly Hypertensive Patients Christopher G. McLane, Stephen J. Zyzanski, and Susan A. Flocke

This study sought indicators of patient noncompliance with medications prescribed for hypertension. A sample of 62 elderly, rural hypertensive patients were interviewed regarding demographics, history and knowledge of hypertension, quality of life, the physician-patient relationship, drug use, and side effects encountered. A five-variable composite was able to detect the patients who were defined as noncompliant. The composite included: 1) number of chronic illnesses, 2) perceived amount of

time the physician spends with the patient, 3) the patient's household composition, 4) family history of hypertension, 5) and whether hypertension affects work or home activities. More accurate identification of noncompliant patients sets the stage for interventions to improve compliance. Am J Hypertens 1995;8:206-209 KEY WORDS: Drug compliance, hypertension, elderly, rural.

any factors influence medication compliance in hypertensive patients including good physician-patient rapport and understanding of the therapeutic regimen. In previous research, poor patient compliance has been associated with a lack of hypertensive symptoms, greater complexity of the medical prescription, and side effects derived from it. 1'2 Because hypertensive patients are usually asymptomatic, any medication that decreases quality of life by causing side effects, such as fatigue, cough, sexual impotence, will have a significant impact on adherence to medical treatment. However, research has shown that elderly hypertensive patients will try harder to adhere to their therapeutic regimen when compared

to their younger counterparts, even in the face of unwanted side effects. 2 Other investigators have identified the importance of therapeutic simplicity in bringing about greater patient compliance. Fewer drugs, a smaller number of tablets, and less side effects have been shown to be associated with more compliant and satisfied patients. 3"4 Much of the recent research examines the newer therapeutic agents such as angiotensin converting enzyme inhibitors. Studies have shown that the ease of administration and low side effect profile of the angiotensin converting enzyme inhibitors have improved patient compliance rate. l"s Similar studies with transdermal clonidine showed that patient satisfaction and compliance increase with the convenience of transdermal therapy. 6 Another problem cited as having an impact on patient compliance was Received April 29, 1994. Accepted September 26, 1994. From the Departmentof FamilyMedicine,CaseWesternReserve the cost of the medications. The increasing costs of University School of Medicine, 10900 Euclid Avenue, Cleveland, medications may be a major factor for elderly patients Ohio. This study was funded by a grant from the Ohio Academyof on fixed incomes. 7 The literature also points out the FamilyPhysiciansFoundation. importance of the physician-patient relationship in Address correspondence and reprint requests to Stephen J. determining the patient's understanding of instrucZyzanski, PhD, Department of Family Medicine, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, tions and the subsequent compliance with the inCleveland, OH 44106-7136. structions, s In fact, one study identified poor physi-

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cian-patient communication as being the single most important factor determining compliance with treatment. 2 A patient's health beliefs also affect compliance. One study found that patients who believed in folk explanations for their hypertension were more noncompliant than patients who believed in the medical explanation. 9 The purpose of this study was to develop a brief set of indicators that would help physicians identify patients likely to have problems taking their hypertensive medications as prescribed. Our specific study population was rural elderly hypertensive patients living in the community. Many of the factors related to compliance issues, as evidenced in the literature, were incorporated into the study with an emphasis on such social issues as the physician-patient relationship, quality of life issues, and the patient's living arrangements. METHODS The sample consisted of patients seen by four primary care physicians in a group practice in rural Pennsylvania, during the period June 1992 to July 1992. Patients w h o were aged 60 years and over and being medically treated for hypertension were asked at their office visit if they would participate. Within a time frame of 6 weeks, 67 patients were invited to participate, and only five refused. Those who agreed (n = 62) had their office blood pressure recorded, and a time for a home interview was scheduled. The same interviewer subsequently visited the patient within 2 weeks of the office visit. The home interview included a second blood pressure reading and questions about demographics, patient history of hypertension, knowledge about hypertension, quality of life, medications and side effects, and the quality of the patient's relationship with the health care provider. After the interview, the interviewer attempted to estimate the percent of time (0% to 100%) that the patient was compliant with taking hypertension medication. This estimate was based, in part, on patient responses to the interview items and in part on the patient's organizational scheme for taking the medication (see Results section for interviewer definition of noncompliance). Patients' self-report of their drug compliance was chosen as the measure of drug compliance (see Results section for reasons). The second phase involved examining the patient's drug compliance in relation to other factors obtained from the interview. All patients were categorized into one of two groups: compliant or noncompliant. Noncompliance was defined as patients who reported that they missed their hypertensive medications more than once per month. Univariate analyses were performed using ×2 statistics for categoric items such as gender, and t tests for

continuous variables such as age. Because of the small sample and exploratory nature of the study, the type I error rate for the univariate analyses was set at an alpha level of 0.10 to allow for trends in the data to be noted. For the multivariable analyses, an alpha of 0.05 was used. A backward elimination stepwise discriminant analysis was performed to determine the most parsimonious set of indicators/items associated with noncompliance. RESULTS A demographic profile of the 62 people interviewed revealed the mean age to be 73 years with 74% of the sample being women. The mean number of years of education was 10 and 69% had both private and Medicare insurance, while 13% had private insurance only. The average number of years since diagnosis of hypertension was 18 with 92% reported having at least one other chronic illness. Sixty-nine percent of the sample had at least one relative with hypertension. Only 21% of the sample currently consumed alcohol and even less, 10%, used tobacco products. All interviewed patients were white, reflecting the fact that the local population is very racially homogeneous. Several variables in the questionnaire were examined as possible estimates of compliance: blood pressure in the office, blood pressure at the home visit, patient self-rating of noncompliance, and the interviewer's estimate. Blood pressure readings were not chosen as compliance measures because they showed no statistical relationship to patient self-report of compliance. When the patient's self-estimate was compared to the interviewer's estimate (interviewer rating compliance was defined as patient taking medication 90% of the time or greater), there was a 92% agreement. Because these two ratings were so similar, we used the patient's self-estimate as the measure of compliance for this study. The distribution of compliance ratings included the following: 49% reported they never miss taking their medication, 27% rarely miss (l/week) and 3% often (once a day). Therefore, by our definition of compliance, those who occasionally, frequently, or often missed taking their medication (24%), were determined to be noncompliant. When the 35 items from the questionnaire were examined in relation to the compliance estimates, five showed an association with noncompliance at P < .05. The five significant univariate associations were for items representing demographics (type of insurance, private showing higher noncompliance rates), quality of life (subjects reporting that high blood pressure does not affect their ability to do work or cleaning had higher noncompliance rates), medical history (subjects having three or more other illnesses had

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higher noncompliance rates), and the physicianpatient relationship (less time spent with the physician per visit for high blood pressure correlated with higher noncompliance rates). Although patients with three or more illnesses, on the average, did take more medications than patients with two or fewer illnesses (3.4 v 1.1, P < .001), analyses adjusting for the number of different medications still showed a strong assodation between number of illnesses and compliance status (P < .01). There were three additional univariate associations at P < .10. Because this was an exploratory study these associations were also noted. Higher noncompliance rates were observed for household composition (spouse or other), family history of hypertension (parent or sibling), and side effects of medication (yes). Two general categories of items exhibited no association with noncompliance: knowledge of hypertension and issues related to the specific drugs the patients were taking. The general knowledge of hypertension category contained three items: the patient's understanding of hypertension, the patient's perception of the cause of hypertension, and the patient's level of worry or concern about hypertension. The general category of specific drugs taken included four items: the number of pills taken per day, the patient's rating of the efficacy of the medication, the number of other prescription drugs taken regularly, and the number of nonprescription drugs taken regularly. The effects of alcohol and tobacco use on noncompliance were also variables of interest; however, too few users were identified for reliable analysis. The last stage of the data analysis involved performing a backward elimination stepwise discriminant analysis of the eight items found significant at P < .10 to determine which ones were independently associated with noncompliance. The analysis identified five items (Table 1) that best characterized noncompliance. Noncompliant patients were more likely to have three or more illnesses, perceive less time spent with the physician, report that their medication does not affect their work activity, live with spouse or others, and have a positive family history of hypertension. Interestingly, the five items represent four of the seven domains hypothesized to be associated with hypertension: history, the physician-patient relationship, quality of life, and demographics. This five-item composite score correctly identified 100% of the patients who were defined as noncompliant (15/ 15) and 70% of the patients defined as compliant (33/ 47). A total of 29 patients were categorized as noncompliant by the composite equation. Thus, 14 compliant patients, or 30%, would be misclassified as noncompliant. Finally, the positive predictive value of the five-item composite for identifying noncompliant patients was 52% (15/29). Thus, slightly more

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TABLE 1. VARIABLES ASSOCIATED WITH NONCOMPLIANCE BY DISCRIMINANT ANALYSIS

Variables Number of illnesses (->3) Physician time with patient (rain) Medication affects work activities (yes) Household composition (alone) Family history of hypertension (yes)

Compliant (means/%) (n = 47)

Noncompliant (means/%) (n = 15)

F

P

35%

64%

8.7

.003

16.4

11.9

6.4

.01

28%

0%

5.6

.02

38%

13%

4.2

.04

64%

87%

3.8

.05

For five variable equation: F - 5.3; df ~ 5, 56; P ~ .001.

than half of the patients (52%) with a score above the cutoff on this five-item composite scale were correctly classified as noncompliant but they accounted for 100% of the noncompliant patients in this sample. DISCUSSION This research suggests that there may be a few simple questions a physician may ask the elderly hypertensive patient to reasonably predict the likelihood of drug compliance. In this study, we found five variables to be independent of the patient's type of hypertensive medication. It is also interesting that for one of the five variables, the physician is the focus (ie, perceived time spent with patients). The characteristic profile of rural elderly noncompliant hypertensive patients as identified in this study is a person who is essentially asymptomatic (hypertension does not affect work or cleaning), and lives with others at home. Patients living alone may be more compliant because they realize that their safety and health are their own responsibility. Also, the noncompliant patients in our sample were quite familiar with hypertension as they often had a family history of high blood pressure. This may remove much of the diagnosis' impact on the patient, especially as these patients had several other chronic illnesses that were more likely to be symptomatic, such as arthritis, diabetes, and congestive heart failure. This study also confirms previous findings that persons aged 60 years and above have better compliance w h e n compared with y o u n g e r counterparts. 10 Our results did confirm many of the factors cited in the literature as having an impact on compliance. We found that one of the strongest predictors of compliance was time spent with the patient, one of the physician-patient relationship items. 2 Our research also

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MEDICATION NONCOMPLIANCEIN HYPERTENSIVEPATIENTS 209

showed that quality of life issues are also important larger sample, at other sites including urban ones. for good patient compliance because patients who Still, we believe that this study provides a starting perceived that their hypertension affected their daily point for physicians to develop strategies that idenactivities were more likely to be compliant. Other tify noncompliant hypertensive patients in their pracstudies have explored the importance of household tice and successfully intervene with these patients to composition on the overall well-being of senior citi- bring about better compliance. zens. One in particular challenged the commonly acREFERENCES cepted belief that an elderly patient living alone is at 1. Juncos LI: Patient compliance and angiotensin conincreased risk for morbidity and mortality. This study verting enzyme inhibitors in hypertension. J Cardio found that elderly people living alone have a greater Pharm 1990;15(suppl 3):$22-$25. propensity to be functionally independent, whereas 2. Clark LT: Improving compliance and increasing conthose living with others are more likely to be depentrol of hypertension: needs of special hypertensive dent. 11 In agreement with this research, our findings populations. Am Heart J 1991;121:664-668. also suggested that elderly people living alone were 3. Morgan TO, Nowson C, Murphy J, et al: Compliance significantly more likely to be compliant. 11 Our reand the elderly hypertensive. Drugs 1986;31(suppl 4): search did not s h o w a difference in compliance 174-183. among the different therapeutic agents; however, our 4. Gonz~lez-Fernandez RA: Usefulness of a systemic hypertension in-hospital educational program. Am J ability to find differences was limited by the small Cardiol 1990;65:1384-1386. sample size and the fact that these patients were tak5. Amadio P, Amadio PB, Cummings DM: Ace inhibiing multiple types of antihypertensive medication. tors: a safe option for hypertension and congestive We also found that cost of medication was not assoheart failure. Post Grad Med 1990;87:223-243. ciated with compliance in our patient sample. The 6. Burris JF: Therapeutic adherence in the elderly: transmajority of our patients (87%) reported that they had dermal clonidine compared to oral verapamil for hyadequate means to pay for their drugs. This may well pertension. Am J Med 1991;91:22S-28S. point to the adequacy of private insurance coverage 7. Taylor JL: Overcoming barriers to blood pressure confor this particular patient population as 82% reported trol in the elderly. Geriatrics 1990;45:35-43. having private insurance in addition to Medicare. 8. Tuck ML: UCLA Geriatric grand rounds: hypertension A potential limitation of this study concerns the use in the elderly. J Am Geriatic Soc 1988;36:630-643. of patient self-report as the measure of compliance. 9. Heurtin-Roberts S: Health beliefs, compliance: hyperStudies have s h o w n that patient self-report does tension. JAMA 1990;264:2864. overestimate compliance but that it also correlates well with trends produced by pill count and urine 10. Guerrero D, Rudd P, Bryant-Kosling C, et al: Antihypertensive medication-taking: investigation of a simsample measures of compliance. 1°'12 Furthermore, ple regimen. Am J Hypertension 1993;6:586-591. one study states that the validity of the traditional pill 11. Zyzanski SJ, Medalie JH, Ford AB, et al: Living arcount is often compromised by its susceptibility to rangements and well-being of the elderly. Fam Med manipulation by patients and by the logistic and ex1989;21:199-205. pense problems associated with its implementation. 10 12. BlackDM, Brand RJ, Greenlick M, et al: Compliance to To further strengthen the results of this study, it treatment for hypertension in elderly patients: The would be helpful to replicate the findings with a SHEP Pilot Study. J Gerontology 1987;42:552-557.