Association between potentially inappropriate medication use and all-cause mortality among older adults with dyslipidemia: a nationwide cohort study

BackgroundPotentially inappropriate medications (PIMs) are known to be associated with adverse outcomes in older adults, yet evidence among those with dyslipidemia--who often experience polypharmacy--remains limited. MethodsWe conducted a nationwide, retrospective cohort study in South Korea using the Health Insurance Review and Assessment Service (HIRA) claims linked to national death records. Adults aged [&ge;]65 years with [&ge;]2 dyslipidemia diagnoses between January and June 2018 were classified as exposed to PIMs per the Drug Utilization Review (DUR) list and followed from a landmark date (July 1, 2018) through June 30, 2024 for all-cause mortality. The primary objective was to compare mortality between the PIM and non-PIM groups; comparisons were conducted using an unadjusted Cox model, an adjusted Cox model, and a propensity score-matched (PSM) cohort (propensity scores estimated via logistic regression including all baseline covariates). Balance was assessed using standardized mean differences, and proportional hazards were checked with scaled Schoenfeld residuals. ResultsOf 943,332 participants, 1.7% received at least one potentially inappropriate medication (PIM) at baseline. Over 6 years, the Kaplan-Meier cumulative mortality was 14.2% in the PIM group versus 11.9% in the non-PIM group (absolute risk difference, 2.3 percentage points; relative risk, 1.19). PIM exposure was significantly associated with increased six-year all-cause mortality risk in both propensity score-matched (HR, 1.12; 95% CI, 1.05-1.19) and multivariable-adjusted analyses (HR, 1.10; 95% CI, 1.05-1.15; both p < 0.001). In subgroup analyses, compared with a single PIM, multiple PIMs showed a numerically higher but non-significant risk (HR, 1.11; 95% CI, 0.79-1.56). ConclusionsAmong older adults with dyslipidemia, PIM prescriptions were associated with a 12% increased risk of all-cause mortality in the PSM cohort. These findings support cautious prescribing and regular medication reviews to minimize risk in this high-risk population.