Polypharmacy in the general population of a Northern Italian area: analysis of administrative data.

INTRODUCTION: The aim of this study was to estimate the prevalence and assess patient-related determinants of polypharmacy in the general population of the Italian area around Udine. MATERIALS AND METHODS: A retrospective cohort study was conducted using administrative databases: drug prescriptions, hospital discharges, ambulatory care prescriptions, exemptions from medical charges. Various definitions of polypharmacy were adopted (co-prescription of multiple medications, use of multiple medications for overlapping time periods). The role of patient's characteristics on polypharmacy was assessed through regression analyses. RESULTS: In 2017, 63.7% of the general population received at least one drug prescription. 25 218 persons were co-prescribed ≥ 5 medications at least once. The prevalence of co-prescriptions among persons ≥ 65 years was 31.7%. 20 793 persons used ≥ 60 DDDs of ≥ 5 medications. The prevalence of all these phenomena was much higher in the elderly than in children and adults. The number of comorbidities significantly affected all types of polypharmacy. CONCLUSIONS: In this area, the prevalence of polypharmacy is high, particularly among the elderly. Age and comorbidities significantly affect the risk. Further research will aim at evaluating the health effects and appropriateness of polyphamacy.