Hospital-level disparities and long-term survival in patients with ST-segment elevation myocardial infarction: evidence from a nationwide cohort study

Background To determine whether initial hospital level is associated with 5-year mortality after ST-segment elevation myocardial infarction (STEMI) in China and to identify factors underlying any differences. Methods The China Acute Myocardial Infarction registry enrolled 12,697 STEMI patients at 108 hospitals in 31 provinces from January 2013 through September 2014, with follow-up through January 1, 2020. Patients were classified by initial admission to provincial-, prefecture-, or county-level hospitals. The primary outcome was 5-year all-cause mortality. Kaplan–Meier and multivariable Cox proportional hazards models were used to assess mortality risk across hospital levels, with competing risk models applied for cardiovascular deaths. Prespecified subgroup analyses tested effect modification. A multiple-mediation framework quantified contributions of patient characteristics and treatment differences. Results 5-year all-cause mortality was 19.8% at provincial-, 25.3% at prefecture-, and 36.2% at county-level hospitals. Compared to provincial-level hospitals, adjusted hazards for all-cause mortality were higher at prefecture (HR, 1.24; 95% CI, 1.11–1.39) and county hospitals (HR, 1.54; 95% CI, 1.34–1.78; P for trend <.001), with similar patterns for cardiovascular mortality. Disparities were most pronounced among patients with overweight/obesity, prior heart failure, cardiogenic shock on admission, or onset-to-arrival time >12 hours. Mediation analysis implicated lower use of primary PCI, older age, and socioeconomic factors as major contributors. Conclusions In this nationwide cohort, initial treatment at lower-level hospitals was associated with substantially higher 5-year mortality after STEMI. Enhancing timely, evidence-based care and strengthening regional referral networks and capacity at lower-tier hospitals may reduce these disparities.