Prevalence of polypharmacy use and association with mortality: a cohort study of elderly people in Southern Brazil, 2014-2017

Abstract

Objective: To characterize prevalence of polypharmacy use and its association with mortality in elderly people. Methods: Prospective cohort (2014 to 2017), with non-institutionalized individuals aged 60 years or over, living in Pelotas, Rio Grande do Sul, Brazil. Association between polypharmacy and mortality was analyzed using Cox regression. Hazard ratios (HR) and their respective 95% confidence intervals (95%CI) were calculated, following the Cox proportional hazards model. Interaction between age group and multimorbidity was considered to be statistically significant when p-value<0.100. Results: Polypharmacy prevalence was 36.1% (95%CI 33.7; 38.6), being higher as age group increased (29.8% in those aged 60-69; 41.3% in those aged 70-79). and 47.8% in those aged 80 years and over). In the adjusted analysis, risk of mortality was 62% higher among elderly people using polypharmacy (HR 1.62; 95%CI 1.10; 2.39), without interaction between age group (p-value 0.750) and multimorbidity (p-value 0.312). The survival analysis demonstrated that the probability of survival was lower in elderly people using polypharmacy (85.6%). Conclusion: Polypharmacy prevalence was found to be higher as age group increased and elderly people using polypharmacy had higher risk of mortality, regardless of age group and presence of multimorbidity.