Is medication use by community-dwelling elderly people influenced by cognitive function?

To determine whether medication use differs by cognitive status among community dwelling elderly, a survey was made of a stratified random sample of 4110 black and white participants, aged 65 or older from the Duke Established Populations for Epidemiologic Studies of the Elderly in five adjacent urban and rural counties in the Piedmont area of North Carolina. Main outcome measures were usage of prescription medications, non-prescription medications, and medicines within therapeutic classes in the previous 2 weeks as determined during an in-home interview; and total number of prescription and non-prescription medications used in the previous 2 weeks. Multivariate analyses, using weighted data adjusted for sampling design, were conducted to assess the association between drug use patterns and cognitive status, as assessed by the Short Portable Mental Status Questionnaire, while adjusting for demographic, health status, and access to health care factors. Participants with cognitive impairment (13.7% of sample) were less likely to use any prescription medications (Adjusted OR = 0.66, 95% CI = 0.48-0.90) or any non-prescription medications (Adjusted OR = 0.71, 95% CI = 0.56-0.89) than cognitively intact subjects. Both groups took a similar number of prescription and non-prescription medications. Those who were cognitively impaired were less likely to take analgesics (Adjusted OR = 0.66, 95% CI = 0.52-0.83), but were more likely to take central nervous system drugs (Adjusted OR = 1.55, 95% CI 1.18-2.04) than those who were cognitively intact. We conclude that drug use patterns by community-dwelling elderly people differ with cognitive status. Future research needs to examine medication use by specific causes of cognitive impairment.