Incidence and risk factors for polypharmacy among elderly people assisted by primary health care in Brazil

Abstract Background Polypharmacy is recognized as a global public health problem and one of the greatest challenges related to the aging population. Few studies have investigated the incidence and risk factors for polypharmacy among elderly individuals. These studies provided important information on the issue but were developed in high-income countries. This study investigates the incidence and risk factors for polypharmacy among elderly people assisted by primary health care over a period of 11 years. Methods This was a census-based prospective longitudinal study that included people aged 60 years or older living in a small municipality in the state of Rio Grande do Sul, Brazil. The baseline occurred in 2010 and the second wave of the study occurred in 2021. The study population consisted of elderly individuals who did not use polypharmacy at baseline and were reinterviewed in 2021 (N = 128). Data collection in the first and second waves was performed through a household survey using a structured questionnaire. The dependent variable was polypharmacy, defined as the simultaneous use of 5 or more drugs. The independent variables included sociodemographic, health and functionality factors. For multivariate analyses, Poisson regression with robust variance was used, estimating the relative risk and 95% confidence intervals. Results The incidence of polypharmacy was 46.1% in the 11-year period. The highest number of health problems was a risk factor for polypharmacy (RR = 1.177; 95% CI 1.093–1.267). Conclusions The incidence of polypharmacy among elderly people assisted in primary health care in Brazil is high. The number of diseases is a risk factor for polypharmacy. These results have implications for future primary health care practices and may support the development of policies, actions and services aimed at reducing polypharmacy and promoting the rational use of drugs in the population at higher risk.