Low health literacy and multiple medications in community-dwelling older adults: a population-based cohort study

OBJECTIVES: Adequate health literacy is important for patients to manage chronic diseases and medications. We examined the association between health literacy and multiple medications in community-dwelling adults aged 50 years and older in England. DESIGN, SETTINGS AND PARTICIPANTS: We included 6368 community-dwelling people of median age 66 years from the English Longitudinal Study of Ageing. Health literacy was assessed at wave 5 (2010/11) with 4 questions concerning a medication label. Four correct answers were categorised as adequate health literacy, otherwise low. Data on medications were collected at wave 6 (2012/13). To examine the difference in the number of medications between low and adequate health literacy, we used zero-inflated negative binomial regression, estimating odds ratio (OR) for zero medication and incidence rate ratios (IRR) for the number of medications, with 95% CIs. Associations were adjusted for demographic, socioeconomic and health characteristics, smoking and cognitive function. We also stratified the analysis by sex, and age (50–64 and ≥65 years). To be comparable with preceding studies, multinomial regression was fitted using commonly used thresholds of polypharmacy (0 vs 1–4, 5–9, ≥10 medications). RESULTS: Although low health literacy was associated with a lower likelihood of being medication-free (OR=0.64, 95% CI: 0.45 to 0.91), health literacy was not associated with the number of medications among those at risk for medication (IRR=1.01, 95% CI: 0.96 to 1.05), and this finding did not differ among younger and older age groups or women. Among men, low health literacy showed a weak association (IRR=1.06, 95% CI: 0.99 to 1.14). Multinomial regression models showed graded risks of polypharmacy for low health literacy. CONCLUSIONS: Although there was no overall association between health literacy and the number of medications, this study does not support the assertion that low health literacy is associated with a notably higher number of medications in men.