The impact of bariatric surgery on retinopathy in patients with type 2 diabetes: a retrospective cohort study

Background: The impact of bariatric surgery on diabetic retinopathy (DR) is unclear. DR might improve after surgery because of improvement in DR risk factors, but the rapid improvement in hyperglycemia after surgery could worsen DR. Objectives: To assess the impact of bariatric surgery on the progression to sight-threatening DR (STDR) in patients with type 2 diabetes mellitus (T2DM) and compare STDR progression in patients with T2DM who underwent bariatric surgery with a group of matched patients receiving routine care between January 2005 and December 2012 at a single center. Setting: Single-center university hospital. Methods: DR was assessed using 2 x 45-degree retinal images obtained from the English National Diabetic Eye Screening Programme. Only patients who had retinal images within 1 year before surgery and at least 1 image after surgery were included in the analysis. STDR was defined as the presence of pre-proliferative/proliferative DR, maculopathy, or laser treatment. The comparator group comprised patients with T2DM who attended the same center for diabetes care and who had not undergone bariatric surgery. Results: This analysis comprised 152 patients (mean age, 50.7 +/- 8.2 yr; baseline body mass index, 49.0 +/- 7.3 kg/m(2)) who were followed-up for 3.0 +/- 1.9 years. Of the 141 patients without STDR at baseline, 8 (5.7%) developed STDR by the end of the study. Of 106 patients with no DR at baseline, 2 (1.9%) developed preproliferative DR. Of 41 patients with background DR at baseline, 5 (12.2%) developed preproliferative DR. Of the 143 patients with no maculopathy at baseline, 8 (5.6%) developed maculopathy. Compared with a matched group for age, glycated hemoglobin, and follow-up duration, the progression to STDR and maculopathy was less in patients who underwent surgery versus those who received routine care (STDR: 5.7% [8/141] versus 12.1% [12/99], P=.075; maculopathy: 5.6% [8/143] versus 15.4% [16/104], P=.01, respectively). Conclusions: After bariatric surgery, patients with T2DM remain at risk for developing STDR, even those who did not have evidence of DR before surgery. However, surgery was associated with a lower progression to STDR or maculopathy compared with routine care. Randomized clinical trials are needed to ascertain the impact of bariatric surgery on DR. (C) 2016 American Society for Metabolic and Bariatric Surgery. All rights reserved.