biostudies-literatureUnknown16(2)Cho HJPolypharmacy may cause adverse health outcomes in the elderly. This study examined the prevalence of continuous polypharmacy and hyper-polypharmacy, factors associated with polypharmacy, and the most frequently prescribed medications among older adults in South Korea. This was a retrospective observational study using National Health Insurance claims data. In total, 7,358,953 Korean elderly patients aged 65 years and older were included. Continuous polypharmacy and hyper-polypharmacy were defined as the use of ≥5 and ≥10 medications, respectively, for both ≥90 days and ≥180 days within 1 year. A multivariate logistic regression analysis was conducted with adjustment for general characteristics (sex, age, insurance type), comorbidities (12 diseases, number of comorbidities, and Elixhauser CClinical and translational science193-205https://www.ebi.ac.uk/biostudies/studies/S-EPMC9926077biostudies-literatureFactors related to polypharmacy and hyper-polypharmacy for the elderly: A nationwide cohort study using National Health Insurance data in South Korea.PMC9926077Yoon SHKim DSChae JCho HJfalseFactors related to polypharmacy and hyper-polypharmacy for the elderly: A nationwide cohort study using National Health Insurance data in South Korea.Polypharmacy may cause adverse health outcomes in the elderly. This study examined the prevalence of continuous polypharmacy and hyper-polypharmacy, factors associated with polypharmacy, and the most frequently prescribed medications among older adults in South Korea. This was a retrospective observational study using National Health Insurance claims data. In total, 7,358,953 Korean elderly patients aged 65 years and older were included. Continuous polypharmacy and hyper-polypharmacy were defined as the use of ≥5 and ≥10 medications, respectively, for both ≥90 days and ≥180 days within 1 year. A multivariate logistic regression analysis was conducted with adjustment for general characteristics (sex, age, insurance type), comorbidities (12 diseases, number of comorbidities, and Elixhauser C2023-01-01T00:00:00Z2023 Feb2026-07-14T20:25:33.417Z2025-04-04T12:42:18.478ZS-EPMC99260773640158710.1111/cts.13438