(V) Polypharmacy and Potential Drug Interactions in the Brazilian Amazon: A Cross-Sectional Population-Based Study, 2019

Saturday, August 27, 2022

8:00 AM – 6:00 PM CEST

Location: Hall E South

Publication Number: 646

Presenting Author(s)

Tais Freire Galvao
– State University of Campinas, Campinas, S�o Paulo, Brazil

Co-Author(s)

Gustavo Magno B. Tiguman
– State University of Campinas, Brazil
Tayanny Margarida M. Almeida Biase
– State University of Campinas, Brazil
Marcus Silva
– Pharmaceutical Sciences Graduate Course, University of Sorocaba, sorocaba, Sao Paulo, Brazil

Background: Concomitant use of multiple medicines may be required in certain situations, but polypharmacy may result in poor outcomes. Investigations on polypharmacy and its effect on interactions in the population setting are scarce.

Objectives: To assess the prevalence of polypharmacy and to investigate the frequency of potential drug interactions in people on polypharmacy.

Methods: We conducted a cross-sectional population-based study in Manaus, Brazil in 2019. Participants aged ≥18 years were selected by probability sampling and interviewed in their households. The primary outcome was polypharmacy (use of ≥5 drugs). Potential drug interactions in polypharmacy participants were also identified and classified according to Micromedex. The prevalence ratios (PR) and 95% confidence intervals (95%CI) of polypharmacy were calculated by Poisson regression with robust variance, following a hierarchical model of proximal and distal variables. Analyses were conducted in Stata 14.2 and considered the complex sampling design.

Results: The study included 2,321 participants. The prevalence of polypharmacy was 2.8% (95%CI 2.1-3.6%) in the general adult population and 8.9% (95%CI 2.8-15.1%) considering exclusively the elderly (≥60 years). Losartan (6.1%), dipyrone (5.4%), acetylsalicylic acid (4.5%) and simvastatin (4.1%) were the most used medicines. Drug interactions were observed in 74.0% of polypharmacy participants; most had ≥4 interactions per person (40.4%), were severe (59.5%) and had regular documentation (51.9%). Polypharmacy was higher among the elderly (PR=3.24; 95% CI 1.25-8.42), people with poor health (PR=2.54; 95% CI 1.14-5.67), previous hospitalizations (PR=1.90; 95% CI 1.09-3.32) and multimorbidity (PR=3.20; 95% CI 1.53-6.67).

Conclusions: Polypharmacy was present in 3 out of 100 adults in Manaus and was higher in people with poorer health outcomes. Three-quarters of individuals on polypharmacy had potential drug interactions. Reducing polypharmacy represents a strategy to prevent severe drug interactions in a population perspective.