Risk Factors Related to Drug Duplication in a Health Services Provider: A Case-control Study

Polypharmacy, defined as the concurrent use of five or more drugs, can lead to drug duplication (DD), which is considered a medication error that increases costs to the health systems. The key objectives of this study are to characterize DD in a population receiving care at a Health Services Provider Institution and identify factors associated with DD. This study was a retrospective case-control study. Controls were selected using 1:4 propensity-score matching based on age, sex, geographic location, and socioeconomic status. This study revealed a 1.67% prevalence of DD over 6 months. The most prescribed drugs were: Levothyroxine, Acetaminophen and Losartan. A logistic regression was used to calculate the odds ratio (OR), which showed a relationship between DD and the number of medications (OR: 1.355, 95% CI: 1.324–1.386), number of pathologies (OR: 1.314, 95% CI: 1.272–1.357), number of emergency cases (OR: 3.470, 95% CI: 1.679–7.170), number of hospitalizations (OR: 1.130, 95% CI: 1.019–1.253), inconsistent drug claim (OR: 2.131, 95% CI: 1.937–2.344), and laboratory test off target (OR: 1.399, 95% CI: 1.228–1.593). The study showed DD prevalence in a health services provider from a low-to-middle income country. The main findings indicated that polypharmacy, suffering from several pathologies, hospitalizations, and visits to emergency departments, increases the risk of DD.