Population-based prevalence of polypharmacy and patterns of medication use in southwestern Iran: A cross-sectional study

Abstract

Background: Pharmaceutical medications are considered an important component of healthcare delivery and there is a need for its rational use; although there have been major improvements in the pharmaceutical sector in the recent past, inappropriate medication use is considered a major threat to patients' health. Therefore, the pattern of medication use should be monitored routinely. The aim of this study was to investigate the population-based prevalence of polypharmacy and the patterns of medication use in southwestern Iran. We also investigated correlates between polypharmacy and patterns of medication use.

Methods: Data from the Khuzestan Comprehensive Health Study (KCHS) which consists information of 30 506 with age range to 20 to 65 years were used. Crude and age-standardized prevalence of polypharmacy and their 95% confidence intervals were estimated for different subpopulations. Multivariable Poisson regression modeling was applied, and adjusted prevalence ratios and their 95% confidence intervals were estimated. The Anatomical Therapeutic Chemical classification system (first and second levels) was used for drug classification in different groups based on age, gender, and socioeconomic status.

Results: Out of 30 506 adults, 93.3% were not on any medications, and age- and gender-standardized prevalence of polypharmacy was 0.24%. The lowest estimated prevalence was among Arab participants (0.13%). The prevalence of polypharmacy was 1.57% among elderly people, and 4.78% among patients with heart diseases. Socioeconomic status was not associated with polypharmacy (prevalence ratio: 0.95; p = 0.573) but was significantly associated with patterns of medications use for alimentary tract and metabolism and nervous system diseases. The most common drug classes were cardiovascular system (3.93%), alimentary tract and metabolism (2.79%), nervous system (1.01%), systemic hormonal preparations (0.69%), and blood and blood-forming organs (0.38%).

Conclusions: The prevalence of polypharmacy is very low in Khuzestan province, especially in the Arab population. Future research is needed to investigate the causes of medication underuse in this population.

Keywords: Iran; epidemiology; medication use; polypharmacy.