Association of Potentially Inappropriate Medications and Geriatric Nutritional Risk Index with Frailty in Elderly Patients with Ischemic Heart Disease

Background/Objectives: Frailty is a clinically significant syndrome in older patients with ischemic heart disease, associated with adverse outcomes including hospitalization, disability, and mortality. This study aimed to evaluate the association of potentially inappropriate medication (PIM) and the Geriatric Nutrition Risk Index (GNRI) with the incidence of frailty among elderly patients with ischemic heart disease (IHD). Methods: This retrospective cohort study enrolled elderly patients with IHD between January 2018 and March 2024. Patients were grouped by PIM use and GNRI levels (<92 vs. ≥92). Cox proportional hazards models assessed the associations of PIM and GNRI with the incidence of frailty. Subgroup and sensitivity analyses evaluated the consistency and robustness of these findings. Results: PIM use was associated with a significantly higher risk of frailty (HR = 3.01, 95% CI = 2.48–3.65) than non-use. Similarly, lower GNRI increased the risk of frailty compared to higher GNRI (HR = 1.31, 95% CI = 1.12–1.54). Patients with both PIM and lower GNRI may have a higher risk of frailty, with an adjusted aHR of 4.09. Subgroup analyses showed significant interactions between GNRI and hypertension. Sensitivity analyses indicated that PIM (aHR = 2.65) and lower GNRI (aHR = 1.14) remained significantly associated with frailty, even after including those with pre-existing frailty. Conclusions: For elderly patients with IHD, both PIM and lower GNRI were significantly associated with the incidence of frailty. These findings suggest that PIM exposure and low GNRI may serve as clinically accessible markers for identifying older IHD patients at elevated risk of frailty.