Incidence of coronary heart disease in type 2 diabetic men and women - Impact of microvascular complications, treatment, and geographic location

OBJECTIVE - Cardiovascular disease (CVD) is the main cause of morbidity/mortality in diabetes. We set forth to determine incidence and identify predictors (including microvascular complications and treatment) of first coronary heart disease (CHD) event in CVD-free type 2 diabetic patients. RESEARCH DESIGN AND METHODS - A cohort of 6,032 women and 5,612 men, sampled from a nationwide network of hospital-based diabetes clinics, was followed up for 4 years. Baseline assessment included retinopathy, nephropathy, and foot ulcers. First CHD events (myocardial infarction, coronary artery bypass grafting, percutaneous transluminal coronary angioplasty, and electrocardiogram-proven angina) were analyzed for 29,069 person-years. RESULTS - The age-standardized incidence rate (per 1,000 person-years) of first CHD event (n = 881) was 28.8 (95% CI 5.4-32.2) in men and 23.3 (20.2-26.4) in women. Major CHD (myocardial infarction, coronary artery bypass grafting, and percutaneous transtuminal coronary angioplasty) was less frequent in women (5.8 [4.3-7.2]) than in men (13.1 [10.9-15.4]; a sex ratio of 0.5 [0.4-0.6]). Incidence rates of all outcomes were higher in patients with microvascular complications (for major CHD, age-adjusted rate ratios were 1.6 [1.2-2.21] in men and 1.5 [1.0-2.2] in women). By multivariate Cox analysis, age and diabetes duration were risk predictors common in both sexes. In men, glycemic control and treated hypertension were additional independent risk factors, but residing in the south was associated with a significant 29% risk reduction. In women, higher triglycerides/lower HDL cholesterol and microvascular complications were independent risk factors. CONCLUSIONS - in CVD-free patients with type 2 diabetes, risk of first CHD event depends on sex, geographic location, and presence of microvascular disease. Hyperglycemia and hypertension, particularly in men, and diabetic dyslipidemia, especially in women, are risk factors amenable to more aggressive treatment.