Objective: To determine the impact of improved glycemic control on the development and progression of retinopathy after the institution of insulin therapy in patients with type 2 diabetes and to assess the relation to IGF-1 and hemostatic variables.
Research design and methods: In a prospective observational study, 45 type 2 diabetic patients were examined at baseline and 1, 3, 6, 12, and 24 months after change to insulin therapy. Retinopathy was graded on fundus photographs using the Wisconsin scale; HbA1c, IGF-1, and hemostatic variables were measured.
Results: During the observation period of 2 years, 23 patients progressed in the retinopathy scale; 8 progressed > or = 3 levels. After 2 years of insulin treatment, HbA1c and IGF-1 were significantly lower than at baseline, whereas the hemostatic variables had not changed significantly. Progression of retinopathy > or = 3 levels was related to the degree of HbA1c reduction, the duration of diabetes, a higher prothrombin fragment 1 + 2 levels (F1 + 2), but not to other hemostatic variables or IGF-1. The relative risk for progression > or = 3 levels was 2.6 when HbA1c had been reduced > or = 3 percent units (95% CI 1.1-6.1).
Conclusions: The magnitude of improvement of HbA1c by the institution of insulin treatment over a 2-year period may be associated with progression of retinopathy in patients with type 2 diabetes.