Use of the Hypoxia–Age–Shock Index at Triage to Predict Mortality in Geriatric STEMI Patients Undergoing Primary PCI

Background and Objectives: Older adults with ST-segment elevation myocardial infarction (STEMI) experience disproportionately high mortality despite advances in reperfusion therapy. The Shock Index (SI) and Age–Shock Index (ASI) offer rapid hemodynamic assessment but do not address hypoxia. The Hypoxia–Age–Shock Index (HASI), which incorporates oxygen saturation (SpO2), may improve early mortality prediction in geriatric STEMI. Materials and Methods: This retrospective cohort study included adult STEMI patients receiving primary percutaneous coronary intervention (PCI) at a tertiary center from 2019 to 2023. A total of 711 patients were analyzed, including 254 aged ≥65 years. SI, ASI, and HASI were calculated using triage vital signs prior to intervention. The primary outcome was in-hospital mortality. Thirty-day mortality was analyzed as a pre-specified secondary endpoint using Kaplan–Meier survival analysis and multivariable Cox regression. Discrimination was assessed using ROC curves with pairwise AUC comparison by DeLong’s test. Results: Elderly patients showed higher creatinine and troponin T levels, lower hemoglobin, and elevated ASI and HASI values (all p < 0.001). They had increased rates of cardiogenic shock (26.8% vs. 14.0%), major adverse events (26.0% vs. 10.1%), and in-hospital mortality (9.4% vs. 3.7%, p = 0.003). Age ≥ 65 years independently predicted 30-day mortality (adjusted HR 2.59, 95% CI 1.34–5.04). Among indices, HASI demonstrated the highest discriminative performance (AUC 0.703 in elderly; 0.743 in younger patients). Conclusions: In geriatric STEMI, HASI demonstrated numerically higher discriminative performance for in-hospital mortality compared with SI and ASI, supporting its use as a simple and rapid triage tool.