Insulin resistance-related factors, but not glycemia, predict coronary artery disease in type 1 diabetes - 10-year follow-up data from the Pittsburgh Epidemiology of Diabetes Complications study

OBJECTIVE - To determine the independent risk factors for coronary artery disease (CAD) in type I diabetes by type of CAD at first presentation. RESEARCH DESIGN AND METHODS - This is a historical prospective cohort study of 603 patients with type 1 diabetes diagnosed before 18 years of age between 1950 and 1980. The mean age and duration of diabetes at baseline were 28 (range 8-47) and 19 years (7-37), respectively, and patients were followed for 10 years. Patients with prevalent CAD were excluded from the study. Electrocardiogram (ECG) ischemia was defined by Minnesota Code (MC) 1.3, 4.1-3, 5.1-3, or 7.1; angina was determined by Pittsburgh Epidemiology of Diabetes Complications (EDC) study physician diagnosis; and hard CAD was determined by angiographic stenosis greater than or equal to50%, revascularization procedure, Q waves (MC 1.1-1.2), nonfatal myocardial h infarction (MI), or CAD death. RESULTS - A total of 108 incident CAD events occurred during the 10-year follow-up: 17 cases of ECG ischemia, 49 cases of angina, and 42 cases of hard CAD (5 CAD deaths, 25 nonfatal MI or major Q waves, and 12 revascularization or greater than or equal to50% stenosis). Blood pressure, lipid levels, inflammatory markers, renal disease, and peripheral vascular disease showed a positive gradient across the groups of no CAD, angina, and hard CAD (P < 0.01, trend analysis, all variables), although estimated glucose disposal rate (eGDR) and physical activity showed inverse associations (P < 0.01, trend analysis, both variables). In addition, depressive symptomatology predicted angina (P = 0.016), whereas HbA, showed no association with subsequent CAD. CONCLUSIONS - These data suggest that although the standard CAD risk factors are still operative in type I diabetes, greater glycemia does not seem to predict future CAD events. In addition, depressive symptomatology predicts angina and insulin resistance (eGDR) predicts hard CAD end points.