Cardiac mortality, diabetes mellitus, and multivessel disease in ST elevation myocardial infarction

Background: In patients with diabetes mellitus presenting with ST elevation myocardial infarction (STEMI) the degree to which cardiac death rates may be attributed to an increased burden of coronary artery disease is not clear. Methods: This prospective observational study examines rates of cardiac death between those with and without diabetes at long term follow up, stratified by presence of multivessel disease (MVD), in consecutive STEMI patients from 5 Australian hospitals. Results: Amongst 2083 patients, 393 patients had diabetes (18.8%), and 810 (38.8%) had MVD. Patients with diabetes were more likely to have MVD 48.6% (191/393) than patients without diabetes 36.6% (619/1690; p <.001). At final follow up (median 3.6 years [IQR 2.4–5.4]) cardiac death occurred in 37/393 diabetic patients and 92/1690 nondiabetic patients (adjusted HR1.67, 95% CI 1.10–2.52). In those with MVD cardiac death occurred in 27/191 diabetic patients, and 54/619 non-diabetic patients (adjusted HR 1.94; 95% CI 1.17–3.23). In single vessel disease (SVD) cardiac death occurred in 10/202 diabetic patients, and 38/1071 non-diabetic patients (adjusted HR 1.37; 95% CI 0.65–2.89). Both diabetes and MVD were independently associated with cardiac death. Conclusions: STEMI patients with diabetes are more likely to have MVD, with an absolute difference in MVD rates of 12%, and higher rates of cardiac death. Randomized trials studying these high risk patients are needed to reduce cardiac mortality in patients with diabetes, MVD and STEMI.