Sudden cardiac death after myocardial infarction in type 2 diabetic patients with no residual myocardial ischemia

Abstract

OBJECTIVE Diabetes mellitus (DM) is a well-established risk factor for coronary artery disease. Nonetheless, it remains unclear whether DM contributes to sudden cardiac death in patients who survive myocardial infarction (MI). The objective of this study was to compare the incidence of sudden cardiac death post-MI in diabetic and nondiabetic patients with no residual myocardial ischemia. RESEARCH DESIGN AND METHODS A total of 610 consecutive post-MI patients referred to a cardiac rehabilitation program with negative exercise stress test were studied. RESULTS Of these, 236 patients had DM at baseline. Over a mean follow-up of 5 years, 67 patients with DM (28.4%) and 76 of 374 patients without DM (20.2%) had died with a hazard ratio (HR) of 1.74 (95% CI: 1.28-2.56; P < 0.001). Patients with DM also had a higher incidence of cardiac death (1.84 [1.16-3.21]; P = 0.01), principally due to a higher incidence of sudden cardiac death (2.14 [1.22-4.23]; P < 0.001). Multiple Cox regression analysis revealed that only DM (adjusted HR: 1.9 [95% CI: 1.04-3.40]; P = 0.04), left ventricular ejection fraction (LVEF) </=30% (3.6 [1.46-8.75]; P < 0.01), and New York Heart Association functional class >II (4.2 [1.87-9.45]; P < 0.01) were independent predictors for sudden cardiac death. Among patients with DM, the 5-year sudden cardiac death rate did not differ significantly among those with LVEF </=30%, LVEF 31-50%, or LVEF >50% (8.8 vs. 7.8 vs. 6.8%, respectively; P = 0.83). CONCLUSIONS Post-MI patients with DM, even in the absence of residual myocardial ischemia clinically, were at higher risk of sudden cardiac death than their non-DM counterparts.