Reduced cardio-renal function accounts for most of the in-hospital morbidity and mortality risk among patients with type 2 diabetes undergoing primary percutaneous coronary intervention for ST-segment elevation myocardial infarction

OBJECTIVE: ST-segment elevation myocardial infarction (STEMI) patients with type 2 diabetes mellitus (DM) have higher in-hospital mortality than those without. Since cardiac and renal functions are the main variables associated with outcome in STEMI, we hypothesized that this prognostic disparity may depend on a higher rate of cardiac and renal dysfunction in DM patients. RESEARCH DESIGN AND METHODS: We retrospectively analyzed 5,152 STEMI patients treated with primary angioplasty. Left ventricular ejection fraction (LVEF) and estimated glomerular filtration rate (eGFR) were evaluated at hospital admission. The primary end point was in-hospital mortality. A composite of in-hospital mortality, cardiogenic shock, and acute kidney injury was the secondary end point. RESULTS: There were 879 patients (17%) with DM. The incidence of LVEF ≤40% (30% vs. 22%), eGFR ≤60 mL/min/1.73 m2 (27% vs. 18%), or both (12% vs. 6%) was higher (P < 0.001 for all comparisons) in DM patients. In-hospital mortality was higher in DM patients than in non-DM patients (6.1% vs. 3.5%; P = 0.002), with an unadjusted odds ratio (OR) of 1.81 (95% CI 1.31-2.49; P < 0.001). However, DM was no longer associated with an increased mortality risk after adjustment for cardiac and renal function (OR 1.03, 95% CI 0.68-1.56; P = 0.89). A similar behavior was observed for the secondary end point, with an unadjusted OR for DM of 1.52 (95% CI 1.25-1.85; P < 0.001) and an OR after adjustment for cardiac and renal function of 1.07 (95% CI 0.85-1.36; P = 0.53). CONCLUSIONS: The study indicates that the increased in-hospital mortality and morbidity of DM patients with STEMI is mainly driven by their underlying cardio-renal dysfunction.