Diabetic retinopathy in people with Type 2 diabetes and obesity treated by Roux-en-Y gastric bypass compared with non-operated controls: with focus on the role of diabetes remission in a cross-sectional and a 6-year follow-up study.

AIM: Whether or not Roux-en-Y gastric bypass (RYGB) and the derived metabolic improvements are beneficial to diabetic retinopathy is controversial. We aimed to determine the presence and development of retinopathy in individuals with obesity and Type 2 diabetes treated by RYGB compared with non-operated controls, and to determine the role of diabetes remission. METHODS: We graded fundus photography using the Wisconsin Epidemiologic Study of Diabetic Retinopathy in 96 individuals with obesity and Type 2 diabetes treated by RYGB 6 years after surgery compared with 48 non-operated controls. In a subsample, we investigated the development of retinopathy over time. In the secondary analysis, we divided the RYGB group according to diabetes remission. RESULTS: RYGB surgery was not statistically associated with less retinopathy [relative risk (RR) 0.82, 95% CI 0.59 to 1.14], when adjusted for diabetes duration, sex, age and BMI. During 5.9 years of follow-up, retinopathy grading in the RYGB group was unchanged, whereas the control group displayed worse grading by 0.69 steps (95% CI 0.18 to 1.19). The RYGB group with diabetes remission (52%) showed a trend towards less retinopathy [adjusted RR (aRR) 0.45; 95% CI 0.19 to 1.06] than controls, and less retinopathy (aRR 0.33; 95% CI 0.11 to 0.94) than the RYGB group without remission in the cross-sectional data. CONCLUSIONS: In a cross-sectional setting, individuals with Type 2 diabetes treated by RYGB showed a tendency towards less retinopathy than non-operated controls, in particular diabetes remission following RYGB was associated with less retinopathy. Moreover after 5.9 years, retinopathy in the RYGB group had progressed less than in the control group. (Clinical Trial Registry No: NCT02625649).