Factors Affecting the Progression of Retinopathy in Type 2 Diabetes

The aim of this study was to identify the factors affecting the progression of retinopathy in patients with type 2 diabetes. 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. 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.  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.