Inadequate health literacy (HL) is associated with impaired healthcare choices leading to poor quality-of-care. Our primary purpose was to estimate the prevalence of inadequate HL among two populations of AARP® Medicare Supplement insureds: sicker and healthier populations; to identify characteristics of inadequate HL; and to describe the impact on patient satisfaction, preventive services, healthcare utilization, and expenditures. Surveys were mailed to insureds in 10 states. Multivariate regression models were used to identify characteristics and adjust outcomes. Among respondents (N = 7334), 23% and 16% of sicker and healthier insureds, respectively, indicated inadequate HL. Characteristics of inadequate HL included male gender, older age, more comorbidities, and lower education. Inadequate HL was associated with lower patient satisfaction, lower preventive service compliance, higher healthcare utilization and expenditures. Inadequate HL is more common among older adults in poorer health, further compromising their health outcomes; thus they may benefit from expanded educational or additional care coordination interventions.
