Incidence and Risk for Developing Proliferative Diabetic Retinopathy after Photocoagulation for Diabetic Maculopathy

Purpose: Diabetic maculopathy (DM) treated with photocoagulation may subsequently progress to proliferative diabetic retinopathy (PDR). However, there is insufficient knowledge about the incidence and risk factors for the development of PDR in patients previously treated for DM. Materials and methods: Survival data was used to analyze prospectively collected epidemiological and clinical data to describe the incidence and risk factors for the occurrence of PDR in all 1,235 patients photocoagulation treated for DM in a defined population from the Aarhus area, Denmark, from January 1. 1993 until December 31. 2016. Results: Among 1,204 (97.5%) of the patients in whom the subsequent clinical history was known, 536 (44.5%) had died and 131 (10.9%) had received panretinal photocoagulation for PDR. The cumulative incidence of developing PDR after photocoagulation for diabetic maculopathy increased with time to reach a plateau around 13% after approximately 15 years. Earlier age at diagnosis of diabetes and higher HbA1c at the time of macular treatment were significant risk factors for the development of PDR, whereas gender, diabetes type, body mass index, known diabetes duration at the time of macular photocoagulation and blood pressure were not significant risk factors. Conclusions: In patients treated with retinal photocoagulation for DM, a tight metabolic control is accompanied with a reduced risk for subsequent progression to PDR. In the treated patients who do not develop PDR, the control interval can be gradually increased with time.