In the training cohort, patients with extended hospital stays demonstrated a higher median age (66 vs 68 years, P < 0.001), lower median hemoglobin (Hb) concentration (13.2 vs 12.8 g/dL, P < 0.001), longer OD (80 vs 85 min, P < 0.001), and a higher incidence of diabetes mellitus (DM, P ═ 0.026), ischemic heart disease (IHD, P ═ 0.011), and previous cerebrovascular accidents (CVA; P < 0.001). The gene discussed is GSTM1; the disease is myocardial ischemia.