Diabetic retinopathy and the risk of coronary heart disease - The Atherosclerosis Risk in Communities Study

OBJECTIVE - We sought to examine the relation of diabetic retinopathy to incident coronary heart disease (CHD). RESEARCH DESIGN AND METHODS - A population-based, prospective cohort study consisting of 1,524 middle-aged individuals with type 2 diabetes without prevalent CHD and stroke at baseline was conducted. Diabetic retinopathy signs were graded from retinal photographs according to the Early Treatment for Diabetic Retinopathy Study severity scale. Incident CHD events (myocardial infarction, fatal CHD, or coronary revascularization) were identified and validated following standardized protocols. RESULTS - in our study, 214 (14.7%) participants had diabetic retinopathy. Over an average follow-up of 7.8 years, there were 209 (13.7%) incident CHD events. After controlling for age, sex, race, study center, fasting glucose, A1C, duration of diabetes, blood pressure, antihypertensive treatment, cigarette smoking, BMI, and lipid profile, the presence of diabetic retinopathy was associated with a twofold higher risk of incident CHD events (hazard rate ratio [HR] 2.07 [95% CI 1.38-3.11]) and a threefold higher risk of fatal CHD (3.35 [1.40-8.01]). Further adjustments for inflammatory markers, carotid artery intima-media thickness, or nephropathy had minimal impact on the association. The increased risk of CHD was significant in both men (1.89 [1.08-3.31]) and women (2.16 [1.16-4.02]) with diabetic retinopathy. CONCLUSIONS - In individuals with type 2 diabetes, the presence of retinopathy signifies an increased CHD risk, independent of known risk factors. Our data support the role of microvascular disease in the pathogenesis of CHD in diabetes.