Reading Between the Lines

Many studies have shown that education is good for your health.^1–10 In the United States, the number of years of school completed is directly related to survival for patients with hypertension,² those who have had a myocardial infarction,³ and the general population.^4–8 Although these links have been recognized for decades, the factors that mediate the relation between education and health are poorly understood. Low educational attainment may affect health indirectly through its association with unemployment, poverty, and the lack of health insurance. Alternatively, low educational attainment may have more direct effects on health by affecting the use of health care services, such as physician visits and preventive services,¹¹ or adherence to recommended medical treatments, such as lifestyle changes, taking medications, and going to scheduled appointments. For example, people with more education are more likely to change their diet or to exercise more in response to a doctor’s recommendation.¹²

Most studies of education and health have relied on the number of school years as the sole measure of education. More recently, studies have begun to use literacy or health literacy, which is the ability to read and comprehend health-related materials, as a more precise indicator of educational attainment.^13–18 Measuring the number of years of school measures the amount of education attempted. However, health literacy reflects what was learned during those years, as well as an individual’s ability to read and comprehend new information. Previous studies have found that patients with inadequate literacy are less likely than patients with adequate literacy to know essential information about their chronic medical conditions, including hypertension,¹⁵ diabetes,¹⁵ and asthma.¹⁶ Similarly, asthmatic patients with inadequate functional health literacy are less likely than those with adequate literacy to know how to use a metered-dose inhaler correctly, even when both types of patients are treated in an asthma clinic with standardized education programs.¹⁶ Patients with low literacy are also less likely to understand discharge instructions following an emergency department visit.^19,20 These findings may partly explain why those with lower reading ability are more likely to be hospitalized, even after adjusting for their demographic characteristics, socioeconomic status, and overall health.¹³

In interviews, patients with limited reading ability frequently report medication errors because they are unable to read prescription labels.²¹ It has not been determined, however, whether they are more likely than patients with adequate functional health literacy to make medication errors and thus less likely to adhere to prescribed medications. A study reported in this issue takes a major step toward elucidating this situation.²² Kalichman and colleagues studied a community sample of HIV-seropositive men and women taking highly active antiretroviral therapy. Patients who did not complete high school and those who had low health literacy were less likely to report they took all prescribed doses during the preceding 2 days. The 20% of patients who were not fully adherent had lower CD4 counts and were more likely to have HIV virus detectable in their blood, and these results predict future adverse health effects. Strict compliance with these rigorous regimens is essential to prevent HIV progression and the development of resistant strains, and patients with low health literacy or low educational attainment may need special assistance to achieve this goal.

Kalichman’s study suggests that low health literacy affects compliance through several factors. First, low literacy may affect compliance directly by decreasing the patient’s comprehension of dosing instructions. Patients with low health literacy often are unable to read and correctly interpret instructions on medication bottles.^23,24 In a recent study, 54% of patients with inadequate literacy were unable to correctly answer a question about when they should take a medicine with a label that read: “Take this medicine on an empty stomach, 1 hour before or 2 hours after meals.”²⁴ Because patients with low literacy cannot read labels, they must remember the instructions given them by their doctor or pharmacist. Therefore, it is not surprising that Kalichman found patients with low literacy were more likely to say they missed taking an antiretroviral dose because they were confused.

Second, low literacy may preclude the use of written reminders or other systems to enhance compliance. In Kalichman’s study, however, patients with low literacy did not report having forgotten to take their medication more often than other patients. Nevertheless, it is difficult to interpret answers to questions asking patients to remember what they forgot, and further studies based on pill counts are needed to answer this question more accurately.

Finally, patients with low literacy may intentionally stop taking a medication or take less medication than prescribed if they do not trust the physician’s treatment plan, do not understand the importance of compliance, or have concerns about side effects. Indeed, patients with low literacy in Kalichman’s study were more likely to report that they missed medication doses because they were having side effects, felt depressed, or were attempting to cleanse their body.

It is important to recognize that indirect pathways between literacy and health behaviors like this one can be just as important as direct pathways. For example, if the inability to read prescription labels causes only some of the missed doses in patients with low literacy, these patients will need more than comprehensible dosing instructions to achieve the high compliance levels of other patients. Patients with low literacy will need more help learning enough about their disease, how their medications work, and the adverse consequences of missing recommended doses. Further studies are also needed to examine whether low literacy diminishes doctor-patient communication, satisfaction, and trust, and whether these effects, in turn, contribute to lower compliance.

Although much remains to be learned about how literacy and education affect compliance and other aspects of health care, it is time to address this problem. When patients are expected to follow extremely complicated medical regimens, such as those for treating HIV and many other chronic diseases, they should be screened at the start of any instructional program to determine their reading ability. The Test of Functional Health Literacy in Adults (TOFHLA) is now available in a short form (the S-TOFHLA) that takes only a few minutes to administer.²⁵ The Rapid Estimate of Adult Literacy in Medicine (REALM) is also available, although this instrument tests word recognition but not reading comprehension or functional literacy.²⁶ Both tests identify individuals who are likely to have poor background health knowledge and difficulty understanding both written and oral health messages. Such individuals can then receive more intensive instructions and follow-up assessments of comprehension and compliance. Before implementing screening, staff should be trained about the extreme shame patients have about low literacy, and staff should know how to address this topic sensitively when they encounter someone who has low literacy.^21,27

Screening patients for low literacy is only the first step. We also need educational programs that can communicate essential information effectively to patients with low literacy and promote compliance with lifestyle modifications, medications, and self-management strategies. Writing for lower grade levels is a step in the right direction. Even with the simplest materials, however, patients with low literacy do not comprehend as well as those with better reading skills.^28,29 Clearly, innovative strategies are needed. Houts and colleagues found that showing patients pictographs during an educational session and having the same pictographs available during a recall session dramatically increased the number of items remembered.³⁰ Preliminary work suggests that this technique is effective even for individuals who read at the second to fourth grade level. Some hospitals have taped pills to cards and added graphics showing the times of day when medications should be taken. Computer programs are available that instruct children with asthma how to decrease their exposure to triggers, and these programs could be adapted to teach adults with low literacy. However, no study has rigorously evaluated whether any of these strategies improve compliance or health outcomes.

We need a national effort to determine which strategies are effective for communicating health information to people with chronic illnesses, whatever their reading ability, language, or culture may be. As medicine advances, we ask patients to learn more and more. Unless there are major strides forward in our ability to communicate essential health information, the “health gap” that currently exists in this country between those with high and low educational attainment is likely to grow.⁸