Prevalence and significance of retinopathy in subjects with type 1 diabetes of less than 5 years' duration screened for the diabetes control and complications trial

OBJECTIVE - The Diabetes Control and Complications Trial (DCCT) demonstrate d the powerful impact of glycemic control on the progression of diabetic re tinopathy. A large number of individuals (2,771) underwent stereoscopic col or photography and fluorescein angiography as part of screening for partici pation in the DCCT. A subgroup of those individuals screened participated i n the DCCT and underwent evaluation of their retinal vasculature semiannual ly for 4-9 years. These data were evaluated to determine how the 2000 Ameri can Diabetes Association position statement would apply to the DCCT experie nce. Specifically, the position statement indicates that the first dilated eye examination should be performed after 3-5 years' duration of diabetes b ecause vision-threatening retinopathy virtually never develops in patients with type 1 diabetes during that interval. RESEARCH DESIGN AND METHODS - We examined the experience of the DCCT in eva luating retinal photographs in 1,613 patients with type 1 diabetes of <5 ye ars' duration and follow-up photographs every 6 months for 4-9 years in 855 members of that group. RESULTS - Of 1,613 subjects with type 1 diabetes of <5 years' duration scre ened for the DCCT, 716 (44.4%) had stereo-color photographic evidence of di abetic retinopathy, and 6 had preproliferative or worse pathology. Fluoresc ein angiography revealed retinopathy in 158 of 713 subjects with no evidenc e of retinopathy on color photographs. Thus, 874 (54.2%) of the original 1, 613 subjects had retinopathy at baseline. DCCT follow-up identified 341 add itional individuals in whom retinopathy was del eloping before 5 years; 1,0 83 of 1,613 (67.1%) individuals screened for the DCCT had retinopathy befor e 5 years' duration of diabetes. Those with retinopathy before 5 years had more rapid three-step progression of vascular pathology than those with no retinopathy. CONCLUSIONS - Dilated eye examinations and retinal photography should be in cluded in the routine management of type 1 diabetes during the first 5 year s to identify the individuals at greatest risk for vision-threatening probl ems.