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

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.