Association of Gastric Bypass Surgery With Risk of Developing Diabetic Retinopathy Among Patients With Obesity and Type 2 Diabetes in Sweden

Abstract

incidence and progression of diabetic retinopathy (DR) after gastric bypass surgery (GBP) in patients with obesity and diabetes could guide the management of these patients.OBJECTIVE To investigate the incidence of diabetic ocular complications in patients with type 2 diabetes after GBP compared with the incidence of diabetic ocular complications in a matched cohort of patients with obesity and diabetes who have not undergone GBP.DESIGN, SETTING, AND PARTICIPANTS Data from 2 nationwide registers in Sweden, the Scandinavian Obesity Surgery Registry and the National Diabetes Register, were used for this cohort study. A total of 5321 patients with diabetes from the Scandinavian Obesity Surgery Registry who had undergone GBP from January 1, 2007, to December 31, 2013, were matched with 5321 patients with diabetes from the National Diabetes Register who had not undergone GBP, based on sex, age, body mass index (BMI), and calendar time (2007)(2008)(2009)(2010)(2011)(2012)(2013). Follow-up data were obtained until December 31, 2015. Statistical analysis was performed from October 5, 2018, to September 30, 2019.EXPOSURE Gastric bypass surgery. MAIN OUTCOMES AND MEASURESIncidence of new DR and other diabetic ocular complications. RESULTSThe study population consisted of 5321 patients who had undergone GBP (3223 women [60.6%]; mean [SD] age, 49.0 [9.5] years) and 5321 matched controls (3395 women [63.8%]; mean [SD] age, 47.1 [11.5] years). Mean (SD) follow-up was 4.5 (1.6) years. The mean (SD) BMI and hemoglobin A 1c concentration at baseline were 42.0 (5.7) and 7.6% (1.5%), respectively, in the GBP group and 40.9 (7.3) and 7.5% (1.5%), respectively, in the control group. The mean (SD) duration of diabetes was 6.8 (6.3) years in the GBP group and 6.4 (6.4) years in the control group. The risk for new DR was reduced in the patients who underwent GBP (hazard ratio, 0.62 [95% CI, 0.49-0.78]; P < .001). The dominant risk factors for development of DR at baseline were diabetes duration, hemoglobin A 1c concentration, use of insulin, glomerular filtration rate, and BMI.CONCLUSIONS AND RELEVANCE This nationwide matched cohort study suggests that there is a reduced risk of developing new DR associated with GBP, and no evidence of an increased risk of developing DR that threatened sight or required treatment.

Outcomes of Diabetic Retinopathy Post-Bariatric Surgery in Patients with Type 2 Diabetes Mellitus

“…The initial search resulted in 231 papers. After duplication removal and application of inclusion and exclusion criteria, 16 articles [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] were included in the qualitative analysis. The flowchart of the research strategy is presented in Figure 1.…”

“…The sample size varied between 20 and 5321 participants for the surgical group, with a total of 6375 T2DM patients who underwent bariatric procedures. In 4 studies [28,35,37,38], a controlled matched group with T2DM patients treated only medically was used to compare the outcomes.…”

“…However, some differences may be a potential source of bias when the total change in DR status is analyzed (Egger's test: 5.0064; p = 0.0014; Begg's test: −0.1757; p = 0.3424). The presence of any DR and the percentages of different stages of DR at baseline varied among studies, from no DR at baseline [38] to only proliferative DR [37]. This was the reason for assessing RoB and heterogeneity of studies within subgroups, based on the analyzed effect: de novo DR, progression, or regression in DR status.…”

“…The method of collecting DR data varied across the reviewed papers. Some used the retrospective data from the national health registries [38], while others documented progression by prospective [25,26,28,31,34,36] or retrospective ophthalmological evaluation [27,29,30,32,33,35,37]. The definition of progression also varied: some authors used the criteria of at least 2 steps by the ETDRS scale; others defined progression as any change in the retinopathy score.…”

“…The comparative outcomes in the reviewed studies are presented in Table 1. In the present review, we identified 16 studies [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39], for a total of 6375 T2DM patients that underwent bariatric surgery in which pre-and post-DR status were analyzed. The percentage of patients with no DR at baseline varied between 30.3 and 100% in the study groups.…”