Cognition and health literacy in patients with hypertension

BACKGROUND: Approximately half of the US population has marginal or inadequate health literacy, a measure highly associated with health outcomes. This measure is often linked to age and education, but recent evidence from patients with chronic heart failure suggests that much of age-related variability in health literacy can be explained by cognitive abilities (e.g., working memory, processing speed). OBJECTIVE: We examined the role of cognitive and sensory abilities as mediators of age and education in determining functional health literacy among patients with hypertension. PARTICIPANTS: Four hundred ninety two community-dwelling adults diagnosed with hypertension (aged 21 to 92 years) participated. They were primarily female (73%), African-American (68%), and reported taking on average 7.8 prescribed medications. MEASUREMENTS: Before participation in a medication adherence intervention study, participants completed a battery of health literacy-related tasks. They completed tests that measured health literacy [Short Test of Functional Health Literacy in Adults (STOFHLA)], cognitive abilities (working memory, processing speed), sensory abilities (visual acuity and hearing), and physical health. RESULTS: Regression analyses showed that health literacy was related to age, education, and race (accounting for 24.4% of variance in STOFHLA scores). Cognitive ability accounted for an additional 24% of variance and greatly reduced the influence of age, education, and race (by 75%, 40%, and 48%, respectively). CONCLUSIONS: When controlling for cognitive and sensory variables, the association of age and education with STOFHLA scores was dramatically reduced. Thus, future interventions aimed at improving self-care for patients with low health literacy should aim to reduce demands on patients' cognitive abilities.