Comparison of Short- and Mid-term Efficacy and the Mechanisms of Gastric Bypass Surgeries on Managing Obese and Nonobese Type 2 Diabetes Mellitus: A Prospective Study

Background and AimsWe targeted to investigate the efficacy and the mechanisms of two gastric bypass surgeries, Roux-en-y Gastric Bypass (RYGB) and Billroth II gastrojejunostomy on managing obese patients with T2DM and nonobese T2DM patients, respectively.MethodsSeven nonobese T2DM patients with gastric cancer submitted to Billroth II gastrojejunostomy were compared with nine obese T2DM patients undergoing RYGB about their baseline characteristics, weight loss and glycemic control, 3 months and 2 years after surgery. Meanwhile, β-cell function, glucagon-like peptide 1 (GLP-1), peptide YY (PYY) and gastric inhibitory polypeptide (GIP) levels were also investigated.ResultsSignificant weight loss and improvement of glycemic control were observed in both groups and in the two follow-up periods. Reduction of body mass index was greater in obese patients with T2DM. The efficacy of Billroth II gastrojejunostomy on controlling blood glucose of nonobese T2DM was similar to that of RYGB on managing obese T2DM. Insulin levels and HOMA-IR were decreased in obese T2DM patients, whereas they remained unchanged in nonobese T2DM patients. Generally, levels of GLP-1 and PYY were increased, whereas GIP levels were decreased in both groups.ConclusionsGlycemic control efficacy of Billroth II gastrojejunostomy on managing nonobese T2DM is similar to that of RYGB on treating obese T2DM in the short- and mid-term. The underlying mechanisms of both surgeries may be related to weight loss and gut hormone modulations.