Effects of Roux-en-Y Gastric Bypass on Type 2 Diabetes Mellitus

Abstract Abstract: Bariatric surgery is the most effective treatment for classes II and III obesity patients. This surgically induced weight loss is associated with better glycemic control and higher type 2 diabetes mellitus (T2DM) remission rate compared to conventional medical therapy. Roux-en-Y gastric bypass (RYGB) is the most commonly technique performed, and its risks and benefits are well known. We sought to assess the effects of one-year post-RYGB on glycemic control and T2DM remission in a tertiary care teaching public hospital in Porto Alegre, Southern Brazil. This retrospective cohort study included all patients submitted to RYGB between 2010 and 2019 at Hospital de Clínicas de Porto Alegre. Type 2 diabetes mellitus remission was defined as the absence of oral antidiabetic medication and insulin use in association with a glycosylated hemoglobin (HbA1c) <6.5% one-year post-RYGB. This study was approved by the local Ethics Committee (2018-0088). A total of 549 RYGB procedures were performed from 2010 to 2019 among patients aged 42.2 ± 10.7 years, mostly women (84.7%), white (88%), and with a body mass index (BMI) of 49.4 ± 8.5 kg/m². The preoperative prevalence of T2DM was 31.2% (n=171), of which 93.6% used oral antidiabetic medication and 15.6% used insulin. Among T2DM patients, 39% used at least two oral antidiabetic drugs in association, most of them being metformin (91%) and sulfonylureas (19.3%). Preoperative fasting plasma glucose and HbA1c were 143 ± 48.1 mg/dL and 7.3 ± 1.6%, respectively, reducing to 93.6 ± 21.3 mg/dL (p<0.001) and 5.4 ± 0.7% (p=0.002), respectively, one year after RYGB. Excess weight loss one-year post-RYGB was 68.7 ± 17.1%, similar between patients with and without T2DM (p=0.48). At 12 months, 77.4% of T2DM patients discontinued their oral antidiabetic drugs or insulin, and the disease remission rate was 71.3%. Bariatric surgery was effective for T2DM remission among classes II and III obesity patients, which is in accordance with the current literature. Support: CNPq, FIPE (HCPA)