Retinal vessel caliber and microvascular and macrovascular disease in type 2 diabetes - XXI: The Wisconsin Epidemiologic Study of Diabetic Retinopathy

Objective: To describe the relationship of retinal arteriolar and venular calibers to the long-term incidence of microvascular and macrovascular complications in people with type 2 diabetes. Design: Population -based prospective study. Participants: One thousand three hundred seventy persons diagnosed to have diabetes at 30 years of age in south central Wisconsin participated in the baseline examination from 1980 to 1982, 987 in the 4-year follow-up, and 533 in the 10-year follow-up. Methods: Computer-assisted grading was used to determine the average caliber of retinal arterioles (central retinal arteriolar equivalent [CRAE]) and retinal venules (central retinal venular equivalent [CRVE]) at all examinations. Main Outcome Measures: Incidence and progression of diabetic retinopathy; incidence of proliferative diabetic retinopathy and macular edema; incidence of nephropathy, neuropathy, and lower extremity amputation; and ischemic heart disease, stroke, and overall mortality. Results: While adjusting for other factors, smaller CRAE was associated with the 14-year cumulative incidence of lower extremity amputation (odds ratio [OR], first vs. second to fourth quartiles, 2.20; 95% confidence interval [CI], 1.14-4.24; P = 0.02), 22-year all-cause mortality (hazard ratio [HR], 1.18; 95% Cl, 1,02-1.38; P = 0.03), and 22-year stroke mortality (HR, 1.47; 95% Cl, 1.04-2.07; P = 0.03) but not with the other end points. Larger CRVE was associated with the 14-year incidence of diabetic nephropathy (OR, fourth vs. first to third quartiles, 2.08; 95% Cl, 1.47-2.94; P<0.001) and 22-year stroke mortality (HR, 1.71; 95% Cl, 1.20-2.44; P = 0.003) but with none of the other end points. Conclusions: Retinal vessel caliber is independently associated with risk of incident nephropathy, lower extremity amputation, and stroke mortality in persons with type 2 diabetes. Measurement of retinal vessel caliber from photographs may provide additional information for the prediction of these events.