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Health literacy and sleep disorders: A review
ARTICLE IN PRESS Sleep Medicine Reviews (2008) 12, 143–151
www.elsevier.com/locate/smrv
CLINICAL REVIEW
Health literacy and sleep disorders: A review Janel E. Hackneya,, Terri E. Weaverb,1, Allan I. Packc,d,2 a
Department of Public Health, Health Care Center ]4, 4400 Haverford Avenue, Philadelphia, PA 19104, USA Biobehavioral and Health Sciences Division, University of Pennsylvania School of Nursing, Claire M. Fagin Hall, 418 Curie Boulevard, Philadelphia, PA 19104-6096, USA c Division of Sleep Medicine/Department of Medicine, University of Pennsylvania School of Medicine, 125 South 31st Street, Suite 2100 Philadelphia, PA 19104-3403, USA d Center for Sleep and Respiratory Neurobiology, University of Pennsylvania School of Medicine, 125 South 31st Street, Suite 2100 Philadelphia, PA 19104-3403, USA b
KEYWORDS Sleep disorders; Health literacy; Patient education; Literacy; Adherence
Summary Sleep medicine is a rapidly growing field with a continuing need to educate its patients. The ability of patients to understand information necessary to make appropriate health care choices and engage in positive health care behaviors is impacted by their health literacy. Low health literacy has been demonstrated to affect health outcomes in numerous disease states. Few interventions to circumvent this have been studied, and even fewer have been successful. Health literacy issues may directly affect a clinician’s ability to care for sleep disorder patients effectively. Further research needs to be done to investigate the prevalence and impact of low health literacy in patients with sleep disorders. & 2007 Published by Elsevier Ltd.
Introduction As the field of sleep medicine grows, the need to educate patients about sleep health becomes more apparent. The general population has not traditionally thought of sleep as an important component to staying healthy. Patients need to understand the role of sleep in maintaining good Corresponding author. Tel.: +1 215 685 7600;
fax: +1 215 685 7379. E-mail addresses: [email protected] (J.E. Hackney), [email protected] (T.E. Weaver), [email protected] (A.I. Pack). 1 Tel.: +1 215 898 2992; fax: +1 215 573 2249. 2 Tel.: +1 215 746 4806; fax: +1 215 746 4814. 1087-0792/$ - see front matter & 2007 Published by Elsevier Ltd. doi:10.1016/j.smrv.2007.07.002
health, and the dangers of sleep disorders. Health literacy is a key component of this education, as it is this skill that allows people to understand health information and make informed health choices. The current health care system places high health literacy demands on patients. Understanding diseases and treatment options, following medication regimens, signing consent forms and filling out insurance forms all require a certain degree of health literacy. This has serious implications for sleep medicine as a whole and obstructive sleep apnea in particular. Given the current prevalence of sleep apnea, and the difficulties in maintaining continuous positive airway pressure (CPAP) adherence, it is necessary for
ARTICLE IN PRESS 144 sleep practitioners to maximize patient understanding of their disease and their treatment. Healthy People 20101 recognizes that lack of health literacy can lead to health care disparities. It has included as part of its goals the need to create effective written health information as well as improve the populations’ health literacy skills. Health literacy has also become a focus of the Institutes of Medicine, prompting ongoing studies to explore the complexities of the problem as well as defining health literacy goals for the public.2 In addition, researchers in sleep medicine have begun to realize the importance of Health Literacy. The National Heart, Lung and Blood Institute/NIH/ DHHS3 have tried to stimulate research on the ‘‘Impact of Sleep educational programs related to healthy sleep habits and sleep literacy or to improved rates of diagnoses and treatment of sleep disorders’’.
What is health literacy? To understand the concept of health literacy, it is first helpful to know the definition of literacy. The National Assessment of Adult Literacy (NAAL)4 defines literacy as ‘‘using printed and written information to function in society, to achieve one’s goals, and to develop one’s knowledge and potential.’’ In 1992 it was reported that 40–44 million American adults were functionally illiterate, and another 53 million had only marginal functional literacy skills. Research has continued in this field on a periodic basis, in an attempt to assess trends in national literacy levels. Preliminary reports from the 2003 NAAL5 indicate that overall, there has been little change. The 2003 NAAL includes the first ever, nationwide attempt to assess health literacy skills. In this survey, the Healthy People 2010 definition was used, as ‘‘The degree to which individuals have the capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions.’’6 This survey revealed that 36% of all adults in this country have only basic or below basic health literacy.7 Health literacy is therefore a constellation of skills. In a framework proposed by Nutbeam,8 functional health literacy employs the basic skills one needs to interact with the health care system. It is this skillset that most closely resembles the definition of health literacy as stated by the NAAL. Communicative/interactive health literacy takes functional health literacy and adds the ability to obtain new information, understand its meaning in context, and use it in a variety of situations.
J.E. Hackney et al. Critical health literacy uses both functional health literacy and communicative/interactive health literacy, and includes more critical thinking skills, as well as the ability to use health information to improve one’s own life. Just as in general literacy, health literacy has a number of domains. Oral literacy are the listening and speaking skills that allow the patient to communicate effectively with their health care provider, and to understand health information that is communicated in a medium other than the printed word. Print literacy comprises the basic reading and writing skills. Print literacy is needed to sound out words, and is equally important in understanding meanings, these skills are required to read patient information pamphlets, understand directions on medication bottles, and even to navigate directions to the doctor’s office. However, the ability to read one type of text does not guarantee the ability to read another type. Text has inherent structure—a prescription bottle has a structure very different from the text found in a newspaper. Like all the components of literacy, print literacy depends on context.2 An additional component of health literacy has been health numeracy. There is as yet no consensus on how this should be defined; however, Golbeck et al.9 have offered the following definition: Health numeracy is the degree to which individuals have the capacity to access, process, interpret, communicate, and act on numerical, quantitative, graphical, biostatistical, and probabilistic health information needed to make effective health decisions. Health numeracy can be further divided into four categories. Basic health numeracy comprises the skills that allow one to recognize numbers, and use them without actually requiring arithmetical skills. For example, it is this skill that would allow patients to count out the correct number of pills from a prescription bottle. It is also this skill that a patient on CPAP would need in order to adjust the setting of an inline heated humidifier. Computational health numeracy allows a patient to use simple mathematical skills to manipulate numbers as needed in simple health care settings. Those with adequate computational health numeracy skills have the ability to manipulate information on a nutrition label to determine the total number of calories in a package of food. Analytical health numeracy involves the use of proportions, percentages, and frequencies, and is a key skill in understanding graphs. This skill becomes particularly important when helping patients understand the graphical representations involved in a
ARTICLE IN PRESS Health literacy and sleep disorders: A review polysomnogram, or when explaining the significance of use patterns in a CPAP adherence graph. Finally, there is statistical health numeracy. This skill requires basic understanding of probabilities, and is often encountered by patients in research settings. Those without a basic understanding of statistical health numeracy will find it difficult to understand common research protocol ingredients such as ‘‘blinding’’ or ‘‘randomization’’. In addition, it is this skill that would allow a patient to make an informed choice between different treatments with different chances of success. Such a skill would be important in weighing the relative merits of CPAP versus surgery versus dental appliances for the treatment of obstructive sleep apnea. All health literacy is contextual, and the health literacy required to manage OSA is no different. Oral, print, and numeracy are clearly essential for optimal OSA management. However, given that CPAP therapy requires facility with a CPAP machine, there is likely another form of health literacy which is required—one which encompasses the mechanical/technical skills needed to apply, troubleshoot, and maintain CPAP machines and the mask interface. As yet, this is unexplored in the health literacy literature.
145 about their disease and the steps needed to modify it. This was particularly striking in the subjects with diabetes, as 73% of the patients with diabetes had attended some form of diabetes education classes.
Diabetes It was the diabetes literature that first convincingly demonstrated that low health literacy could lead to poor health outcomes. Schillinger et al.13 conducted a cross-sectional observational study of 408 patients with diabetes. They found that inadequate health literacy was independently associated with poor glycemic control and higher rates of diabetic retinopathy. This association remained true even after adjusting for sociodemographic factors, duration of illness, degree of social support, and presence of depressive symptoms. In a study by Endres et al.14 women with pregestational diabetes and low health literacy were more likely to have several risk factors associated with poor birth outcomes – unplanned pregnancy, no discussion beforehand with their obstetrician or endocrinologist, and no taking of folic acid prior to their pregnancy.
Cancer
Health literacy and disease outcomes There are many studies in the last decade that have tried to determine the association (if any) between health literacy levels and disease outcomes. Several studies have looked at a variety of different chronic diseases. In a study of 2923 Medicare enrollees, approximately one-third had inadequate or marginal health literacy. Those with inadequate health literacy reported, after adjusting for prevalence of chronic conditions, health risk behaviors and socio-demographic characteristics, worse physical functioning and mental health, as well as more difficulty in activities of daily living and limitations due to physical health.10 Sudore et al.,11 looking at an elderly population, demonstrated that limited health literacy was associated with an almost two-fold increase in mortality even after adjusting for multiple variables including socio-economic and presence of co-morbid conditions. In a study by Williams et al.,12 402 subjects with hypertension and 114 subjects with diabetes were assessed to determine their functional health literacy and knowledge of their chronic disease. Forty-eight percent of all subjects had inadequate functional health literacy. Those with low health literacy demonstrated significantly less knowledge
Poor health literacy has been shown to lead to poor acceptance of health prevention measures. This is particularly pronounced when it comes to cancer screening. In a study of 205 Latina women, those with low health literacy were less likely to participate in cervical cancer screening. Women with inadequate functional health literacy in Spanish were 16.7 times less likely to have ever had a Papanicolaou (Pap) test than women with adequate health literacy, even after adjusting for insurance status, education, age, years in the United States, and source of health care.15 Lindau et al.16 demonstrated in a multiethnic cohort that women with lower health literacy were less likely to know the purpose of a Pap test, and less likely to know what to do if informed they had an abnormal one. Poor health literacy was a better predictor of knowledge about cervical cancer screening than ethnicity or education. Guerra et al.17 demonstrated that inadequate functional health literacy is associated with less knowledge about and use of colorectal cancer screening tests. However, this association was not independent of other sociodemographic factors. In a study of 97 Latina women, 52% demonstrated inadequate health literacy. Having adequate functional health literacy
ARTICLE IN PRESS 146 was significantly associated with ever having had a mammogram.18 Thus, health literacy determines the effectiveness of screening measures that might be adapted for detection of common disorders. This will likely apply to screening approaches to sleep disorders.
HIV Health literacy skills are particularly important for those patients with complex management strategies, such as HIV/AIDS. In a multiethnic cohort of 339 patients with HIV-AIDS, Kalichman and Rompa19 demonstrated significant correlations between health literacy and health status. Nearly onequarter of all patients demonstrated low health literacy when tested. Those with lower health literacy had significantly lower CD4 cell counts and significantly higher viral loads. They were also less likely to know their own CD4 count or viral load, and less likely to understand what these markers mean. Those with lower health literacy were also less likely to be taking antiretroviral medication, and were less knowledgeable about their disease and treatment options. A previous study by Kalichman et al.20 had shown health literacy to be an independent predictor of self-reported adherence to anti-retroviral therapy in patients who were HIV positive. They concluded that interventions are needed to address this issue. Thus, health literacy affects the adherence to complex treatments. While we do not know currently if this applies to treatment of sleep disorders, there is every reason to believe that it will.
Asthma For those with life-long chronic disease, health literacy skills play an important part in daily management. Recently, Mancuso and Rincon21 demonstrated that poor health literacy was associated both directly and indirectly with poor longitudinal asthma outcomes. Gazmararian et al.,22 in a study designed to investigate the association of health literacy to knowledge of chronic disease, assessed 115 patients with asthma in terms of their knowledge of their specific disease and their overall health literacy. Those with inadequate health literacy (24% of subjects) had significantly less knowledge about their disease or how to manage it. They concluded that there are many opportunities to improve patients’ knowledge of their chronic disease.
J.E. Hackney et al. Poor health literacy has been shown not only to be associated with lack of asthma knowledge, but also with poor metered dose inhaler (MDI) technique. In a study by Paasche-Orlow et al.,23 seventythree asthma patients were assessed on their health literacy, their asthma medication knowledge, and their MDI technique. Of the 73 subjects enrolled, 16 (22%) were found to have inadequate health literacy, and this was significantly associated with lower asthma medication knowledge and worse MDI technique. They were then given one-on-one 30 min education sessions tailored to correct their particular deficiencies. After the education session, health literacy was no longer associated with knowledge or technique. Similar results were found by Williams et al.24 They demonstrated in an urban public hospital that inadequate literacy was common and correlated with improper use of MDI.
Measuring health literacy The research literature currently relies on two tests of health literacy. The first is the Rapid Estimate of Adult Literacy in Medicine (REALM). Patients read and pronounce 66 items of varying syllables and difficulty. The words are medical terms that one would commonly encounter while navigating the health care system. The score of 0–66 can be converted into one of four reading grade levels. The entire test can be administered in 2–5 min, and its validity and reliability have been established by correlation with older standard literacy tests.25 A shortened version of the REALM has since been devised—the REALM-R26—which contains only eight items. It is designed to be a rapid screening test, and can be administered in less than 2 min. However, extensive studies to determine reliability and validity have not yet been reported. The REALM has limitations. While it tests print literacy, and touches on oral literacy, it does not test numeracy at all. A Spanish language version of the test is not possible due to pronunciation considerations.2 In addition, a recent study comparing REALM performance in African-American and Caucasian adults found a considerable discrepancy in scores even when stratified by education level.27 Thus, there is a suggestion of racial bias in the test. The second widely used test is the Test of Functional Health Literacy in Adults (TOFHLA).28 In its original form, it has 50 reading comprehension items and 17 numeracy items. The reading passages are taken from standard literature a patient might receive while navigating the health care
ARTICLE IN PRESS Health literacy and sleep disorders: A review system: instructions for prep before an upper gastrointestinal series, an informed consent form, and the ‘‘Rights and Responsibilities’’ section of a Medicaid application. Scores can be divided into inadequate, marginal, and adequate health literacy. While it has excellent validity and reliability, it can take up to 22 min to administer. The TOFHLA was shortened to four numeracy items and two reading passages (S-TOFHLA), thereby reducing the administration time from 22 to 12 min. The S-TOFHLA has similar validity and reliability to its longer predecessor, but is much more practical due to the time required to use it.29 There is a Spanish language version of both the TOFHLA and the S-TOFHLA, and they seem to have comparable validity and reliability.30 However, while the S-TOFHLA does test print literacy and numeracy, it does not test for oral literacy. And while both the REALM and the S-TOFHLA use texts based on health care, neither of them explores the myriad literacy skills needed to manage one’s own health, both within and outside the health care system. In addition, health literacy is contextual, and the information needed varies depending on the health issues of the individual. Nath et al.31 recognized this, and developed a literacy tool designed specifically for patients with diabetes. More health literacy assessment tools are needed in specific disease areas, such as sleep disorders, in order to capture the particular skills necessary to manage particular disease states.
Interventions in health literacy In an attempt to improve general health literacy through library outreach, Parker and Kreps32 have outlined some basic strategies. Use of these, however, is not limited to the library sciences, but can be used by clinicians and health education programs of all types. General health literacy education programs attempt to improve oral, print, and numeracy skills by working through school systems, as well as clinics and hospitals. However, these kinds of programs work on a very long timeline, and often rely heavily on written material that is already too complex for the average user. In addition, their broad base may make it difficult for patients to apply in the very specific conditions of their health care needs. Message design programs tend to be more specific, and they have the potential to have great impact on the field of sleep medicine. Through the use of tenets from ‘‘The Plain Language Initiative’’ from the NIH, these
147 types of programs attempt to revamp patient educational materials to make them more accessible. Redesigning pamphlets, adding use of video demonstrations and graphics, and translating them to give them both relevant language and cultural contexts conveyed information more effectively. There are very few patient specific interventions that have been studied in regards to outcome. The use of audiotapes has been studied, with mixed results. Santo et al.33 systematically reviewed studies that evaluated the efficacy of audiotapes for patient education. While patient satisfaction for these tapes was consistently high, the efficacy of these tapes to improve health knowledge or behavioral change was inconclusive. Similar results have been seen with computerized education tools. Gerber et al.34 randomized subjects to either receive standard clinic care or supplemental education via a computer-based multimedia application. While those in the intervention group demonstrated increases in perceived susceptibility to diabetes complications when compared with the control group, there was no significant difference in hemoglobin A1C, diabetes knowledge or self-efficacy, BMI, or blood pressure. In addition, though the increases in perceived susceptibility to diabetes complications were greatest in those with low health literacy, it was the low health literacy subjects who spent the least amount of time on the computer. Another intervention study looked at HIV treatment adherence. In a randomized pilot study, conducted by van Servellen et al.35 Eighty-five subjects with HIV were assigned to receive either an intervention aimed at treatment adherence, or to receive standard clinical care. The intervention group received five group educational sessions regarding HIV knowledge and communication skills, followed by several months of case-management sessions with nurse practitioners. HIV health literacy and medication adherence were measured at several points. Compared with the control group, the intervention group showed significant improvement from baseline in their HIV-specific health literacy. While there was a trend towards improved adherence to therapy, admittedly only based on self-report, this difference was not significant. Not all interventions are tailored at patients with diabetes. Seligman et al.36 studied the effects of notifying physicians when their patients had low health literacy. Physicians were randomized to receive either a note stating that a patient had limited health literacy, or received no notification. Those physicians in the group that received notification were more likely to use management strategies, such as involving a patient’s family
ARTICLE IN PRESS 148 members, using pictures and diagrams, or referring to a nutritionist.
Implications of health literacy for sleep disorders No studies to date have looked at the relationships between sleep disorder outcomes and health literacy. However, sleep disorders share many common features with those disease entities that have been studied. Conditions such as restless leg syndrome, obstructive sleep apnea, and insomnia are chronic and require a combination of behavioral and pharmacological treatment modalities to manage. Restless leg syndrome is a chronic disease with considerable effects on quality of life; however, it has been shown to be both under diagnosed and under treated.37 Part of the problem in diagnosis of RLS may be the subjective nature of the symptoms, and the difficulty many patients have in describing them. The words patients use to describe these sensations vary greatly from person to person, and may not seem to warrant medical attention to a patient with poor health literacy. The sleep medicine community has already acknowledged the difficulty in diagnosing this disease in patient populations where language and communication skills are lacking. In response, new criteria for the diagnosis of restless leg syndrome in children and cognitively impaired elderly were developed.38 While these populations are an extreme example of the barriers in communication between provider and patient, they serve as a reminder that language and literacy skills are a key component in diagnosing disease. Those with poor health literacy skills may need extra consideration when it comes to eliciting information about signs and symptoms of disease. For those patients who receive a diagnosis and are begun on treatment, difficulties may continue to arise due to the nature of the medications used. The dopamine agonists are now the first-line agents for treatment of RLS. However, it has been noted that these medications themselves can cause daytime sleepiness—often the very symptom that brought patients to their doctors in the first place. Those patients with poor health literacy skills may find this confusing. Augmentation and rebound from dopaminergic agents also present special challenges to those with poor health literacy. Augmentation is a worsening of restless legs syndrome symptoms in response to therapy. It often involves a change of timing of symptoms, to 2 h earlier than was experienced
J.E. Hackney et al. prior to treatment. However, it can include increased intensity of the sensations or a decreased efficacy of medication.37 Rebound is the development of symptoms in the morning hours. Each responds to changes in medication regimens. However, patients with inadequate health literacy skills have been shown to have limited capacity to manage their medications39 as well as decreased adherence to complex medication regimens.40 Those with poor health literacy have a particular difficulty in correctly identifying their medications. Combine this with epidemiologic data demonstrating that restless legs syndrome increases with age, and is often found in patients with other co-morbid conditions such as hypertension, diabetes and depression41 which are treated pharmacologically, and the complexity becomes clear. If a patient with several disorders and multiple medications already has difficulty being adherent due to poor health literacy skills, then a change in the medication regime becomes that much more difficult to manage. Those suffering from chronic insomnia may also find themselves in a similar predicament. The evaluation of insomnia often involves the use of complex sleep diaries and logs. They are also used to monitor progress when a patient undergoes cognitive and behavioral therapies. However, the information obtained in these logs is known to correlate poorly with objective information obtained from polysomnography and actigraphy42 and probably best represents the patient’s perception of their sleep difficulties. Yet, given the complexity of some of these diaries, those with poor health literacy may have particular difficulty filling them out with any accuracy, thus lowering their utility for evaluation and management of insomnia. Those with chronic insomnia may also often have difficulty executing strategies developed through cognitive and behavioral therapies. Treatment options such as proper sleep hygiene, stimulus control therapy, and sleep restriction therapy require no small amount of self-management skill on the part of the patient. However, those with low health literacy have been shown to have poor selfcare behaviors in other chronic illnesses, such as asthma and HIV, as described earlier. And for those patients for whom pharmacologic treatment is started, clinicians should proceed with caution. Davis et al.43 recently demonstrated that patients with low literacy are 3.4 times less likely to correctly interpret prescription medication warning labels, such as the warning many sleep aids have that they should not be taken with alcoholic beverages.
ARTICLE IN PRESS Health literacy and sleep disorders: A review Obstructive sleep apnea is another chronic sleep disorder which is estimated to affect 4–9% of the general adult population.44 While CPAP is a known effective treatment, studies show patient adherence to this treatment in general populations is only 40–60%.45–48 The current literature does not demonstrate any reliable predictors of CPAP adherence. However, it is known that patterns of adherence are established early, even within the first week of treatment, and that these early patterns are predictive of later patterns of use.45,47 Thus, it is likely that predictors of CPAP adherence include patient characteristics that exist both prior to and in the early stages of treatment; one characteristic could be degree of health literacy. Indeed, some research has shown that self-efficacy may be a predictor of CPAP adherence.49,50 As discussed previously, health literacy may be related to health outcomes in general, and compliance to therapy in particular. However, the mechanism by which health literacy affects health outcomes remains unknown. Could health literacy be a surrogate marker for socioeconomic status? According to the National Adult Literacy Survey,4 those with the lowest levels of health literacy were more likely to be in poverty and receive public assistance. Those in the highest levels of health literacy were more likely to be employed, and had higher earnings. They were also more likely to work in managerial and professional jobs and worked more weeks of the year. However, the studies looking at health literacy as it affects outcomes in various disease entities like diabetes13 and HIV,20 as well as general health outcomes10,11 found low health literacy to be associated with poor outcomes even after adjusting for socioeconomic factors. Another theory is that those with low health literacy have subsequently low self-efficacy, and thus are less able to adhere to their treatment regimen.2 Thus, there is a need for studies looking specifically at the prevalence of poor health literacy and low self-efficacy in the sleep apnea population, as well as their role in determining CPAP adherence and outcomes. In the future, intervention studies to improve health literacy are likely to be needed. Thus, the developing field of health literacy is very relevant to both diagnosis and management of many sleep disorders. There is a need for research in application of concepts derived from health literacy to sleep medicine and development of new tools relevant to specific sleep disorders. In the absence of specific information about the role of health literacy in management of sleep disorders, practitioners should become familiar with the
149 general concepts of health literacy. Until specific research becomes available, they need to extrapolate from research in other chronic disorders as to how low health literacy might impact their management of common chronic sleep disorders and what interventions are available to them.
Practice points Health literacy points to remember: 1. Health literacy is a collection of skills used by patients to make appropriate health care choices. 2. Low health literacy is associated with poor health outcomes in various diseases and may impact a sleep clinician’s ability to treat his/her patients. 3. Clinicians should use health literacy assessments routinely, which may reveal a patient’s level of comprehension.
Research agenda Future research in this area should include: 1. The prevalence of low health literacy in sleep disorder populations. 2. The relationship between health literacy, self-efficacy, and adherence in sleep disorder populations. 3. Development of interventions designed to improve health literacy in low health literacy populations.
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ARTICLE IN PRESS Health literacy and sleep disorders: A review 41. Phillips B, Hening W, Britz P, et al. Prevalence and correlates of restless legs syndrome: results from the 2005 National Sleep Foundation Poll. Chest 2006;129(1): 76–80. 42. Sateia MJ, Doghramji K, Hauri PJ, et al. Evaluation of chronic insomnia. An American Academy of Sleep Medicine Review. Sleep 2000;23(2):243–308. 43. Davis TC, Wolf MS, Bass 3rd PF, et al. Low literacy impairs comprehension of prescription drug warning labels. J Gen Int Med 2006;21(8):847–51. 44. Young T. The occurrence of sleep-disordered breathing among middle-aged adults. N Engl J Med 1993;328(17): 1230–5. 45. Weaver TE, Kribbs NB, Pack AI, et al. Night-to-night variability in CPAP use over the first three months of treatment. Sleep 1997;20(4):278–83.
151 46. Engleman HM, Martin SE, Douglas NJ. Compliance with CPAP therapy in patients with the sleep apnoea/hypopnoea syndrome. Thorax 1994;49(3):263–6. 47. Kribbs NB, Pack AI, Kline LR, et al. Objective measurement of patterns of nasal CPAP use by patients with obstructive sleep apnea. Am Rev Resp Dis 1993;147(4):887–95. 48. Krieger J, Kurtz D, Petiau C, et al. Long-term compliance with CPAP therapy in obstructive sleep apnea patients and in snorers. Sleep 1996;19(9 Suppl.):S136–43. 49. Stepnowsky Jr. CJ, Marler MR, Ancolia-Israel S. Determinants of nasal CPAP compliance. Sleep Med 2002;3(3):239–47. 50. Weaver TE, Maislin G, Dinges DF, et al. Self-efficacy in sleep apnea: instrument development and patient perceptions of obstructive sleep apnea risk, treatment benefit, and volition to use continuous positive airway pressure. Sleep 2003;26(6):727–32.
www.elsevier.com/locate/smrv
CLINICAL REVIEW
Health literacy and sleep disorders: A review Janel E. Hackneya,, Terri E. Weaverb,1, Allan I. Packc,d,2 a
Department of Public Health, Health Care Center ]4, 4400 Haverford Avenue, Philadelphia, PA 19104, USA Biobehavioral and Health Sciences Division, University of Pennsylvania School of Nursing, Claire M. Fagin Hall, 418 Curie Boulevard, Philadelphia, PA 19104-6096, USA c Division of Sleep Medicine/Department of Medicine, University of Pennsylvania School of Medicine, 125 South 31st Street, Suite 2100 Philadelphia, PA 19104-3403, USA d Center for Sleep and Respiratory Neurobiology, University of Pennsylvania School of Medicine, 125 South 31st Street, Suite 2100 Philadelphia, PA 19104-3403, USA b
KEYWORDS Sleep disorders; Health literacy; Patient education; Literacy; Adherence
Summary Sleep medicine is a rapidly growing field with a continuing need to educate its patients. The ability of patients to understand information necessary to make appropriate health care choices and engage in positive health care behaviors is impacted by their health literacy. Low health literacy has been demonstrated to affect health outcomes in numerous disease states. Few interventions to circumvent this have been studied, and even fewer have been successful. Health literacy issues may directly affect a clinician’s ability to care for sleep disorder patients effectively. Further research needs to be done to investigate the prevalence and impact of low health literacy in patients with sleep disorders. & 2007 Published by Elsevier Ltd.
Introduction As the field of sleep medicine grows, the need to educate patients about sleep health becomes more apparent. The general population has not traditionally thought of sleep as an important component to staying healthy. Patients need to understand the role of sleep in maintaining good Corresponding author. Tel.: +1 215 685 7600;
fax: +1 215 685 7379. E-mail addresses: [email protected] (J.E. Hackney), [email protected] (T.E. Weaver), [email protected] (A.I. Pack). 1 Tel.: +1 215 898 2992; fax: +1 215 573 2249. 2 Tel.: +1 215 746 4806; fax: +1 215 746 4814. 1087-0792/$ - see front matter & 2007 Published by Elsevier Ltd. doi:10.1016/j.smrv.2007.07.002
health, and the dangers of sleep disorders. Health literacy is a key component of this education, as it is this skill that allows people to understand health information and make informed health choices. The current health care system places high health literacy demands on patients. Understanding diseases and treatment options, following medication regimens, signing consent forms and filling out insurance forms all require a certain degree of health literacy. This has serious implications for sleep medicine as a whole and obstructive sleep apnea in particular. Given the current prevalence of sleep apnea, and the difficulties in maintaining continuous positive airway pressure (CPAP) adherence, it is necessary for
ARTICLE IN PRESS 144 sleep practitioners to maximize patient understanding of their disease and their treatment. Healthy People 20101 recognizes that lack of health literacy can lead to health care disparities. It has included as part of its goals the need to create effective written health information as well as improve the populations’ health literacy skills. Health literacy has also become a focus of the Institutes of Medicine, prompting ongoing studies to explore the complexities of the problem as well as defining health literacy goals for the public.2 In addition, researchers in sleep medicine have begun to realize the importance of Health Literacy. The National Heart, Lung and Blood Institute/NIH/ DHHS3 have tried to stimulate research on the ‘‘Impact of Sleep educational programs related to healthy sleep habits and sleep literacy or to improved rates of diagnoses and treatment of sleep disorders’’.
What is health literacy? To understand the concept of health literacy, it is first helpful to know the definition of literacy. The National Assessment of Adult Literacy (NAAL)4 defines literacy as ‘‘using printed and written information to function in society, to achieve one’s goals, and to develop one’s knowledge and potential.’’ In 1992 it was reported that 40–44 million American adults were functionally illiterate, and another 53 million had only marginal functional literacy skills. Research has continued in this field on a periodic basis, in an attempt to assess trends in national literacy levels. Preliminary reports from the 2003 NAAL5 indicate that overall, there has been little change. The 2003 NAAL includes the first ever, nationwide attempt to assess health literacy skills. In this survey, the Healthy People 2010 definition was used, as ‘‘The degree to which individuals have the capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions.’’6 This survey revealed that 36% of all adults in this country have only basic or below basic health literacy.7 Health literacy is therefore a constellation of skills. In a framework proposed by Nutbeam,8 functional health literacy employs the basic skills one needs to interact with the health care system. It is this skillset that most closely resembles the definition of health literacy as stated by the NAAL. Communicative/interactive health literacy takes functional health literacy and adds the ability to obtain new information, understand its meaning in context, and use it in a variety of situations.
J.E. Hackney et al. Critical health literacy uses both functional health literacy and communicative/interactive health literacy, and includes more critical thinking skills, as well as the ability to use health information to improve one’s own life. Just as in general literacy, health literacy has a number of domains. Oral literacy are the listening and speaking skills that allow the patient to communicate effectively with their health care provider, and to understand health information that is communicated in a medium other than the printed word. Print literacy comprises the basic reading and writing skills. Print literacy is needed to sound out words, and is equally important in understanding meanings, these skills are required to read patient information pamphlets, understand directions on medication bottles, and even to navigate directions to the doctor’s office. However, the ability to read one type of text does not guarantee the ability to read another type. Text has inherent structure—a prescription bottle has a structure very different from the text found in a newspaper. Like all the components of literacy, print literacy depends on context.2 An additional component of health literacy has been health numeracy. There is as yet no consensus on how this should be defined; however, Golbeck et al.9 have offered the following definition: Health numeracy is the degree to which individuals have the capacity to access, process, interpret, communicate, and act on numerical, quantitative, graphical, biostatistical, and probabilistic health information needed to make effective health decisions. Health numeracy can be further divided into four categories. Basic health numeracy comprises the skills that allow one to recognize numbers, and use them without actually requiring arithmetical skills. For example, it is this skill that would allow patients to count out the correct number of pills from a prescription bottle. It is also this skill that a patient on CPAP would need in order to adjust the setting of an inline heated humidifier. Computational health numeracy allows a patient to use simple mathematical skills to manipulate numbers as needed in simple health care settings. Those with adequate computational health numeracy skills have the ability to manipulate information on a nutrition label to determine the total number of calories in a package of food. Analytical health numeracy involves the use of proportions, percentages, and frequencies, and is a key skill in understanding graphs. This skill becomes particularly important when helping patients understand the graphical representations involved in a
ARTICLE IN PRESS Health literacy and sleep disorders: A review polysomnogram, or when explaining the significance of use patterns in a CPAP adherence graph. Finally, there is statistical health numeracy. This skill requires basic understanding of probabilities, and is often encountered by patients in research settings. Those without a basic understanding of statistical health numeracy will find it difficult to understand common research protocol ingredients such as ‘‘blinding’’ or ‘‘randomization’’. In addition, it is this skill that would allow a patient to make an informed choice between different treatments with different chances of success. Such a skill would be important in weighing the relative merits of CPAP versus surgery versus dental appliances for the treatment of obstructive sleep apnea. All health literacy is contextual, and the health literacy required to manage OSA is no different. Oral, print, and numeracy are clearly essential for optimal OSA management. However, given that CPAP therapy requires facility with a CPAP machine, there is likely another form of health literacy which is required—one which encompasses the mechanical/technical skills needed to apply, troubleshoot, and maintain CPAP machines and the mask interface. As yet, this is unexplored in the health literacy literature.
145 about their disease and the steps needed to modify it. This was particularly striking in the subjects with diabetes, as 73% of the patients with diabetes had attended some form of diabetes education classes.
Diabetes It was the diabetes literature that first convincingly demonstrated that low health literacy could lead to poor health outcomes. Schillinger et al.13 conducted a cross-sectional observational study of 408 patients with diabetes. They found that inadequate health literacy was independently associated with poor glycemic control and higher rates of diabetic retinopathy. This association remained true even after adjusting for sociodemographic factors, duration of illness, degree of social support, and presence of depressive symptoms. In a study by Endres et al.14 women with pregestational diabetes and low health literacy were more likely to have several risk factors associated with poor birth outcomes – unplanned pregnancy, no discussion beforehand with their obstetrician or endocrinologist, and no taking of folic acid prior to their pregnancy.
Cancer
Health literacy and disease outcomes There are many studies in the last decade that have tried to determine the association (if any) between health literacy levels and disease outcomes. Several studies have looked at a variety of different chronic diseases. In a study of 2923 Medicare enrollees, approximately one-third had inadequate or marginal health literacy. Those with inadequate health literacy reported, after adjusting for prevalence of chronic conditions, health risk behaviors and socio-demographic characteristics, worse physical functioning and mental health, as well as more difficulty in activities of daily living and limitations due to physical health.10 Sudore et al.,11 looking at an elderly population, demonstrated that limited health literacy was associated with an almost two-fold increase in mortality even after adjusting for multiple variables including socio-economic and presence of co-morbid conditions. In a study by Williams et al.,12 402 subjects with hypertension and 114 subjects with diabetes were assessed to determine their functional health literacy and knowledge of their chronic disease. Forty-eight percent of all subjects had inadequate functional health literacy. Those with low health literacy demonstrated significantly less knowledge
Poor health literacy has been shown to lead to poor acceptance of health prevention measures. This is particularly pronounced when it comes to cancer screening. In a study of 205 Latina women, those with low health literacy were less likely to participate in cervical cancer screening. Women with inadequate functional health literacy in Spanish were 16.7 times less likely to have ever had a Papanicolaou (Pap) test than women with adequate health literacy, even after adjusting for insurance status, education, age, years in the United States, and source of health care.15 Lindau et al.16 demonstrated in a multiethnic cohort that women with lower health literacy were less likely to know the purpose of a Pap test, and less likely to know what to do if informed they had an abnormal one. Poor health literacy was a better predictor of knowledge about cervical cancer screening than ethnicity or education. Guerra et al.17 demonstrated that inadequate functional health literacy is associated with less knowledge about and use of colorectal cancer screening tests. However, this association was not independent of other sociodemographic factors. In a study of 97 Latina women, 52% demonstrated inadequate health literacy. Having adequate functional health literacy
ARTICLE IN PRESS 146 was significantly associated with ever having had a mammogram.18 Thus, health literacy determines the effectiveness of screening measures that might be adapted for detection of common disorders. This will likely apply to screening approaches to sleep disorders.
HIV Health literacy skills are particularly important for those patients with complex management strategies, such as HIV/AIDS. In a multiethnic cohort of 339 patients with HIV-AIDS, Kalichman and Rompa19 demonstrated significant correlations between health literacy and health status. Nearly onequarter of all patients demonstrated low health literacy when tested. Those with lower health literacy had significantly lower CD4 cell counts and significantly higher viral loads. They were also less likely to know their own CD4 count or viral load, and less likely to understand what these markers mean. Those with lower health literacy were also less likely to be taking antiretroviral medication, and were less knowledgeable about their disease and treatment options. A previous study by Kalichman et al.20 had shown health literacy to be an independent predictor of self-reported adherence to anti-retroviral therapy in patients who were HIV positive. They concluded that interventions are needed to address this issue. Thus, health literacy affects the adherence to complex treatments. While we do not know currently if this applies to treatment of sleep disorders, there is every reason to believe that it will.
Asthma For those with life-long chronic disease, health literacy skills play an important part in daily management. Recently, Mancuso and Rincon21 demonstrated that poor health literacy was associated both directly and indirectly with poor longitudinal asthma outcomes. Gazmararian et al.,22 in a study designed to investigate the association of health literacy to knowledge of chronic disease, assessed 115 patients with asthma in terms of their knowledge of their specific disease and their overall health literacy. Those with inadequate health literacy (24% of subjects) had significantly less knowledge about their disease or how to manage it. They concluded that there are many opportunities to improve patients’ knowledge of their chronic disease.
J.E. Hackney et al. Poor health literacy has been shown not only to be associated with lack of asthma knowledge, but also with poor metered dose inhaler (MDI) technique. In a study by Paasche-Orlow et al.,23 seventythree asthma patients were assessed on their health literacy, their asthma medication knowledge, and their MDI technique. Of the 73 subjects enrolled, 16 (22%) were found to have inadequate health literacy, and this was significantly associated with lower asthma medication knowledge and worse MDI technique. They were then given one-on-one 30 min education sessions tailored to correct their particular deficiencies. After the education session, health literacy was no longer associated with knowledge or technique. Similar results were found by Williams et al.24 They demonstrated in an urban public hospital that inadequate literacy was common and correlated with improper use of MDI.
Measuring health literacy The research literature currently relies on two tests of health literacy. The first is the Rapid Estimate of Adult Literacy in Medicine (REALM). Patients read and pronounce 66 items of varying syllables and difficulty. The words are medical terms that one would commonly encounter while navigating the health care system. The score of 0–66 can be converted into one of four reading grade levels. The entire test can be administered in 2–5 min, and its validity and reliability have been established by correlation with older standard literacy tests.25 A shortened version of the REALM has since been devised—the REALM-R26—which contains only eight items. It is designed to be a rapid screening test, and can be administered in less than 2 min. However, extensive studies to determine reliability and validity have not yet been reported. The REALM has limitations. While it tests print literacy, and touches on oral literacy, it does not test numeracy at all. A Spanish language version of the test is not possible due to pronunciation considerations.2 In addition, a recent study comparing REALM performance in African-American and Caucasian adults found a considerable discrepancy in scores even when stratified by education level.27 Thus, there is a suggestion of racial bias in the test. The second widely used test is the Test of Functional Health Literacy in Adults (TOFHLA).28 In its original form, it has 50 reading comprehension items and 17 numeracy items. The reading passages are taken from standard literature a patient might receive while navigating the health care
ARTICLE IN PRESS Health literacy and sleep disorders: A review system: instructions for prep before an upper gastrointestinal series, an informed consent form, and the ‘‘Rights and Responsibilities’’ section of a Medicaid application. Scores can be divided into inadequate, marginal, and adequate health literacy. While it has excellent validity and reliability, it can take up to 22 min to administer. The TOFHLA was shortened to four numeracy items and two reading passages (S-TOFHLA), thereby reducing the administration time from 22 to 12 min. The S-TOFHLA has similar validity and reliability to its longer predecessor, but is much more practical due to the time required to use it.29 There is a Spanish language version of both the TOFHLA and the S-TOFHLA, and they seem to have comparable validity and reliability.30 However, while the S-TOFHLA does test print literacy and numeracy, it does not test for oral literacy. And while both the REALM and the S-TOFHLA use texts based on health care, neither of them explores the myriad literacy skills needed to manage one’s own health, both within and outside the health care system. In addition, health literacy is contextual, and the information needed varies depending on the health issues of the individual. Nath et al.31 recognized this, and developed a literacy tool designed specifically for patients with diabetes. More health literacy assessment tools are needed in specific disease areas, such as sleep disorders, in order to capture the particular skills necessary to manage particular disease states.
Interventions in health literacy In an attempt to improve general health literacy through library outreach, Parker and Kreps32 have outlined some basic strategies. Use of these, however, is not limited to the library sciences, but can be used by clinicians and health education programs of all types. General health literacy education programs attempt to improve oral, print, and numeracy skills by working through school systems, as well as clinics and hospitals. However, these kinds of programs work on a very long timeline, and often rely heavily on written material that is already too complex for the average user. In addition, their broad base may make it difficult for patients to apply in the very specific conditions of their health care needs. Message design programs tend to be more specific, and they have the potential to have great impact on the field of sleep medicine. Through the use of tenets from ‘‘The Plain Language Initiative’’ from the NIH, these
147 types of programs attempt to revamp patient educational materials to make them more accessible. Redesigning pamphlets, adding use of video demonstrations and graphics, and translating them to give them both relevant language and cultural contexts conveyed information more effectively. There are very few patient specific interventions that have been studied in regards to outcome. The use of audiotapes has been studied, with mixed results. Santo et al.33 systematically reviewed studies that evaluated the efficacy of audiotapes for patient education. While patient satisfaction for these tapes was consistently high, the efficacy of these tapes to improve health knowledge or behavioral change was inconclusive. Similar results have been seen with computerized education tools. Gerber et al.34 randomized subjects to either receive standard clinic care or supplemental education via a computer-based multimedia application. While those in the intervention group demonstrated increases in perceived susceptibility to diabetes complications when compared with the control group, there was no significant difference in hemoglobin A1C, diabetes knowledge or self-efficacy, BMI, or blood pressure. In addition, though the increases in perceived susceptibility to diabetes complications were greatest in those with low health literacy, it was the low health literacy subjects who spent the least amount of time on the computer. Another intervention study looked at HIV treatment adherence. In a randomized pilot study, conducted by van Servellen et al.35 Eighty-five subjects with HIV were assigned to receive either an intervention aimed at treatment adherence, or to receive standard clinical care. The intervention group received five group educational sessions regarding HIV knowledge and communication skills, followed by several months of case-management sessions with nurse practitioners. HIV health literacy and medication adherence were measured at several points. Compared with the control group, the intervention group showed significant improvement from baseline in their HIV-specific health literacy. While there was a trend towards improved adherence to therapy, admittedly only based on self-report, this difference was not significant. Not all interventions are tailored at patients with diabetes. Seligman et al.36 studied the effects of notifying physicians when their patients had low health literacy. Physicians were randomized to receive either a note stating that a patient had limited health literacy, or received no notification. Those physicians in the group that received notification were more likely to use management strategies, such as involving a patient’s family
ARTICLE IN PRESS 148 members, using pictures and diagrams, or referring to a nutritionist.
Implications of health literacy for sleep disorders No studies to date have looked at the relationships between sleep disorder outcomes and health literacy. However, sleep disorders share many common features with those disease entities that have been studied. Conditions such as restless leg syndrome, obstructive sleep apnea, and insomnia are chronic and require a combination of behavioral and pharmacological treatment modalities to manage. Restless leg syndrome is a chronic disease with considerable effects on quality of life; however, it has been shown to be both under diagnosed and under treated.37 Part of the problem in diagnosis of RLS may be the subjective nature of the symptoms, and the difficulty many patients have in describing them. The words patients use to describe these sensations vary greatly from person to person, and may not seem to warrant medical attention to a patient with poor health literacy. The sleep medicine community has already acknowledged the difficulty in diagnosing this disease in patient populations where language and communication skills are lacking. In response, new criteria for the diagnosis of restless leg syndrome in children and cognitively impaired elderly were developed.38 While these populations are an extreme example of the barriers in communication between provider and patient, they serve as a reminder that language and literacy skills are a key component in diagnosing disease. Those with poor health literacy skills may need extra consideration when it comes to eliciting information about signs and symptoms of disease. For those patients who receive a diagnosis and are begun on treatment, difficulties may continue to arise due to the nature of the medications used. The dopamine agonists are now the first-line agents for treatment of RLS. However, it has been noted that these medications themselves can cause daytime sleepiness—often the very symptom that brought patients to their doctors in the first place. Those patients with poor health literacy skills may find this confusing. Augmentation and rebound from dopaminergic agents also present special challenges to those with poor health literacy. Augmentation is a worsening of restless legs syndrome symptoms in response to therapy. It often involves a change of timing of symptoms, to 2 h earlier than was experienced
J.E. Hackney et al. prior to treatment. However, it can include increased intensity of the sensations or a decreased efficacy of medication.37 Rebound is the development of symptoms in the morning hours. Each responds to changes in medication regimens. However, patients with inadequate health literacy skills have been shown to have limited capacity to manage their medications39 as well as decreased adherence to complex medication regimens.40 Those with poor health literacy have a particular difficulty in correctly identifying their medications. Combine this with epidemiologic data demonstrating that restless legs syndrome increases with age, and is often found in patients with other co-morbid conditions such as hypertension, diabetes and depression41 which are treated pharmacologically, and the complexity becomes clear. If a patient with several disorders and multiple medications already has difficulty being adherent due to poor health literacy skills, then a change in the medication regime becomes that much more difficult to manage. Those suffering from chronic insomnia may also find themselves in a similar predicament. The evaluation of insomnia often involves the use of complex sleep diaries and logs. They are also used to monitor progress when a patient undergoes cognitive and behavioral therapies. However, the information obtained in these logs is known to correlate poorly with objective information obtained from polysomnography and actigraphy42 and probably best represents the patient’s perception of their sleep difficulties. Yet, given the complexity of some of these diaries, those with poor health literacy may have particular difficulty filling them out with any accuracy, thus lowering their utility for evaluation and management of insomnia. Those with chronic insomnia may also often have difficulty executing strategies developed through cognitive and behavioral therapies. Treatment options such as proper sleep hygiene, stimulus control therapy, and sleep restriction therapy require no small amount of self-management skill on the part of the patient. However, those with low health literacy have been shown to have poor selfcare behaviors in other chronic illnesses, such as asthma and HIV, as described earlier. And for those patients for whom pharmacologic treatment is started, clinicians should proceed with caution. Davis et al.43 recently demonstrated that patients with low literacy are 3.4 times less likely to correctly interpret prescription medication warning labels, such as the warning many sleep aids have that they should not be taken with alcoholic beverages.
ARTICLE IN PRESS Health literacy and sleep disorders: A review Obstructive sleep apnea is another chronic sleep disorder which is estimated to affect 4–9% of the general adult population.44 While CPAP is a known effective treatment, studies show patient adherence to this treatment in general populations is only 40–60%.45–48 The current literature does not demonstrate any reliable predictors of CPAP adherence. However, it is known that patterns of adherence are established early, even within the first week of treatment, and that these early patterns are predictive of later patterns of use.45,47 Thus, it is likely that predictors of CPAP adherence include patient characteristics that exist both prior to and in the early stages of treatment; one characteristic could be degree of health literacy. Indeed, some research has shown that self-efficacy may be a predictor of CPAP adherence.49,50 As discussed previously, health literacy may be related to health outcomes in general, and compliance to therapy in particular. However, the mechanism by which health literacy affects health outcomes remains unknown. Could health literacy be a surrogate marker for socioeconomic status? According to the National Adult Literacy Survey,4 those with the lowest levels of health literacy were more likely to be in poverty and receive public assistance. Those in the highest levels of health literacy were more likely to be employed, and had higher earnings. They were also more likely to work in managerial and professional jobs and worked more weeks of the year. However, the studies looking at health literacy as it affects outcomes in various disease entities like diabetes13 and HIV,20 as well as general health outcomes10,11 found low health literacy to be associated with poor outcomes even after adjusting for socioeconomic factors. Another theory is that those with low health literacy have subsequently low self-efficacy, and thus are less able to adhere to their treatment regimen.2 Thus, there is a need for studies looking specifically at the prevalence of poor health literacy and low self-efficacy in the sleep apnea population, as well as their role in determining CPAP adherence and outcomes. In the future, intervention studies to improve health literacy are likely to be needed. Thus, the developing field of health literacy is very relevant to both diagnosis and management of many sleep disorders. There is a need for research in application of concepts derived from health literacy to sleep medicine and development of new tools relevant to specific sleep disorders. In the absence of specific information about the role of health literacy in management of sleep disorders, practitioners should become familiar with the
149 general concepts of health literacy. Until specific research becomes available, they need to extrapolate from research in other chronic disorders as to how low health literacy might impact their management of common chronic sleep disorders and what interventions are available to them.
Practice points Health literacy points to remember: 1. Health literacy is a collection of skills used by patients to make appropriate health care choices. 2. Low health literacy is associated with poor health outcomes in various diseases and may impact a sleep clinician’s ability to treat his/her patients. 3. Clinicians should use health literacy assessments routinely, which may reveal a patient’s level of comprehension.
Research agenda Future research in this area should include: 1. The prevalence of low health literacy in sleep disorder populations. 2. The relationship between health literacy, self-efficacy, and adherence in sleep disorder populations. 3. Development of interventions designed to improve health literacy in low health literacy populations.
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