Prevalence of and factors associated with polypharmacy and potential drug interactions in adults in Manaus city, Brazil: a cross-sectional population-based study, 2019

Abstract

Objective: To assess the prevalence and factors associated with polypharmacy and the presence of potential drug interactions among these individuals in Manaus, estado do Amazonas, Brazil, in 2019. Methods: Cross-sectional population-based study conducted with adults aged ≥18 years. Among people on polypharmacy (≥5 medicines), the presence of drug interactions was investigated in the icromedex database. Prevalence ratios (PR) were calculated by Poisson regression with robust variance, following hierarchical analysis and considering the complex sample design. Results: Out of the 2,321 participants were included, 2.8% (95%CI 2.1;3.6) were on polypharmacy, of which 74.0% presented drug interactions, with four or more interactions per person (40.4%) and high severity (59.5%) being the most frequent. Polypharmacy was higher among the elderly (PR=3.24 – 95%CI 1.25;8.42), poor health (PR=2.54 – 95%CI 1.14;5.67), previous hospitalization (PR=1.90 – 95%CI 1.09;3.32) and multimorbidity (PR=3.20 – 95%CI 1.53;6.67). Conclusion: Polypharmacy was more frequent among the elderly and people with health problems, who potentially had more drug interactions.