Cognition and health literacy in patients with hypertension

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).

We examined the role of cognitive and sensory abilities as mediators of age and education in determining functional health literacy among patients with hypertension.

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.

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.

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).

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.