Prevalence of Polypharmacy in Elderly Population Worldwide: A Systematic Review and Meta-Analysis

Background: Polypharmacy (PP) is common in elderly population and associated with some adverse clinical outcomes and increases healthcare burdens. We performed this systemic review and meta-analysis to estimate worldwide prevalence of PP and explore associated factors in the elderly. Methods: The PubMed, Web of Science, Cochrane Library, and Ovid EMBASE databases were searched for studies published until May 30, 2022. We included observational studies representative of general patients aged >= 60 in which PP was defined as multiple drugs >= 5. Studies were excluded if only a particular group of the elderly population (e.g., with diabetes) were included. The primary outcome was the prevalence of PP. Random-effect models were employed to estimate the overall or variable-specific pooled estimates of PP. Secondary outcomes were hyperpolypharmacy (HPP, defined as multiple drugs >= 10) and PP prevalence based on different study years, genders, locations, populations, and so forth. Results: We included 122 original observational studies with an overall population of 57 328 043 individuals in the meta-analysis. The overall prevalence of PP and HPP in the elderly population worldwide was 39.1% (95% confidence interval [CI], 35.5%-42.7%) and 13.3% (95% CI, 10.4%-16.5%), respectively. The prevalence of PP in Europe, Oceania, North America, Asia, and South America was 45.8% (95% CI, 41.5%-50.2%), 45.5% (95% CI, 26.7%-64.3%), 40.8% (95% CI, 29.8%-51.6%), 29.0% (95% CI, 20.0%-38.0%), and 28.4% (95% CI, 24.0%-32.8%), respectively (p < 0.01). Multivariate meta-regressions showed geographical regions of Europe or North America, age >= 70, and residence from nursing homes were independently associated with higher PP prevalence. Conclusions: Nearly 40% of the elderly population is exposed to PP. The prevalence of PP is significantly higher in elderly individuals aged 70 or older, in developed regions and in nursing homes. It is important to focus on avoiding inappropriate PP in this population to address the growing burden of PP.