Factors Affecting the Progression of Retinopathy in Type 2 Diabetes

Background and purpose: The aim of this study was to identify the factors affecting the progression of retinopathy in patients with type 2 diabetes. Materials and methods: In this historical prospective cohort study, 728 patients with type 2 diabetes, attending Sari Tooba Clinic, were followed up for retinopathy. Data analysis was performed using accelerated failure time Weibull regression model in Stata V12. Results: The mean and median times until retinopathy progression was 17.24 and 15 years, respectively. A total of 304 (41.8%) patients developed retinopathy and 424 (58.2%) were considered as right censoring observations. The incidence of retinopathy was 40.5 per 1000 in person per year, and 5-year incidence rate from 5 to 25-year follow up were 7%, 15%, 24%, 41%, and 49%, respectively. The accelerated failure time Weibull regression showed age at the time of diagnosis of diabetes (P< 0.001) and at first referral (P< 0.001), nephropathy (P= 0.122), hypertension (P< 0.001), and hemoglobin A1c level (P= 0.034) as the factors affecting the progression of retinopathy.  Conclusion: Early diagnosis of diabetes and controlling hypertension and blood glucose as well as periodic examinations for early detection of nephropathy can delay the progression of retinopathy.