Polypharmacy among community-dwelling elderly in Singapore: Prevalence, risk factors and association with medication non-adherence

Background: Polypharmacy, given its link with drug interactions, potentially inappropriate medications and medication non-adherence, may pose a significant health risk, especially among the elderly. A comprehensive understanding of the epidemiology of polypharmacy is essential for countries facing population ageing and growing chronic disease burden, like Singapore. Objectives: We assessed the prevalence and risk factors of polypharmacy (⩾5 prescription medications) among community-dwelling elderly in Singapore and established the association of polypharmacy with medication non-adherence. Methods: We used data from a national sample of 1499 community-dwelling elderly aged ⩾66 years. Using logistic regression, we assessed the association of socio-demographic, health and healthcare use variables with polypharmacy, and polypharmacy with medication non-adherence. Results: The weighted prevalence of polypharmacy was 14.5%. In multivariable analysis, elderly who were men (versus women), with ⩾2 (versus 0–1) chronic diseases, aged ⩾85 (versus 66–69) years, and of Malay and Indian (versus Chinese) ethnicity were significantly more likely to have polypharmacy; healthcare use variables were not associated. Polypharmacy was significantly correlated with medication non-adherence. Conclusions: The prevalence of polypharmacy among community-dwelling elderly in Singapore is lower than that reported in other countries; however, polypharmacy is associated with medication non-adherence. Elderly subgroups, defined by gender, health status, age and ethnicity, who are at a higher risk of polypharmacy will benefit from medication review and de-prescribing services.