Quality use of medicines and health outcomes among a cohort of community dwelling older men: an observational study

Abstract

To determine the prevalence of potentially suboptimal medication use and association with adverse outcomes. A prospective, observational cohort study of 4260 community-dwelling older men from Perth, Western Australia (mean age of 77 ± 3.6 years) was conducted. Follow-up was for 4.5 years (or until death, if sooner). Cox proportional hazard models were used to explore associations between suboptimal medication use and prospective clinical outcomes. Logistic regression analyses were used to explore predictors of a fall in the previous 12 months. Use of potentially inappropriate medicines (48.7%), polypharmacy (≥5 medications, 35.8%) and potential under-utilization (56.7%) were highly prevalent, and overall 82.3% of participants reported some form of potentially suboptimal medication use. A self-reported history of falls in the previous 12 months was independently associated with the number of medicines taken (odds ratio [OR]= 1.06, 95% confidence interval [CI] 1.02, 1.09) and use of one or more potentially inappropriate medicines (OR = 1.23, 95% CI 1.04, 1.45). After adjusting for age, co-morbidity, smoking status, body mass index, hypertension and educational attainment, the number of medicines reported was associated with admission to hospital (hazard ratio [HR]= 1.04, 95% CI 1.03, 1.06), cardiovascular events (HR = 1.09, 95% CI 1.06, 1.12) and all cause mortality (HR = 1.04, 95% CI 1.00, 1.07). Use of one or more potentially inappropriate medicines was associated with admission to hospital (HR = 1.16, 95% CI 1.08, 1.24). Potential under-utilization was associated with cardiovascular events (HR = 1.20, 95% CI 1.03, 1.40). These data suggest that both medication over-use and under-use occur frequently among older men and may be harmful.