Progression of retinopathy in insulin-treated type 2 diabetic patients.

OBJECTIVE—To study the progression of retinopathy 3 years after initiation of insulin therapy. RESEARCH DESIGN AND METHODS—In a prospective, observational case-control study, 42 type 2 diabetic patients were examined at baseline and 1, 3, 6, 12, 24, and 36 months after change to insulin therapy. Retinopathy was graded based on fundus photographs using the Wisconsin scale; HbA1c and IGF-1 were measured. RESULTS—During the observation period of 3 years, 26 patients progressed in the retinopathy scale; 11 patients progressed at least three levels. After 3 years of insulin therapy, HbA1c and IGF-1 were significantly lower than at baseline. Progression of retinopathy greater than or equal to three levels was related to high IGF-1 levels. CONCLUSIONS—A relationship was found between high IGF-1 levels at 3 years and progression of retinopathy in type 2 diabetic patients