Decreasing the risk of diabetic retinopathy in a study of case management: the California Medi-Cal Type 2 Diabetes Study.

OBJECTIVE Diabetic retinopathy affects >60% of people with type 2 diabetes during the first 2 decades of the disease and is ameliorated by good glycemic control. This study tested whether intensive diabetes case management could prevent or delay diabetic retinopathy in patients with established type 2 diabetes. RESEARCH DESIGN AND METHODS This study was part of a randomized, controlled clinical trial of diabetes case management in type 2 diabetes in southern California counties serving low income ethnic minority populations. Subjects were randomized to intervention (diabetes case management) or control (traditional treatment) groups. Subjects with at least two retinal photographs (n = 149) were included in this analysis to assess the effect of intervention on development or progression of diabetic retinopathy. RESULTS Progression of retinopathy in the intervention group was not significantly less than in the control group (P = 0.226). However, those in the intervention group with no evidence of retinopathy at baseline were less likely to develop diabetic retinal changes (5/48) during a mean follow-up of 23.1 months than those in the control group (10/34, chi(2) = 4.805, P = 0.028). This difference remained significant in a logistic regression model that controlled for potential confounders (odds ratio 5.35 [95% CI 1.14-25.12]). CONCLUSIONS This study shows that a relatively short duration of case management instituted before the onset of clinically identifiable retinopathy significantly diminished the risk of developing retinopathy in patients with type 2 diabetes. The findings also emphasized the retinal disease burden in this population, with development and progression of retinopathy occurring in <2 years.