Glucose Metabolism After Gastric Banding and Gastric Bypass in Individuals With Type 2 Diabetes: Weight Loss Effect

Abstract

OBJECTIVEThe superior effect of Roux-en-Y gastric bypass (RYGB) on glucose control compared with laparoscopic adjustable gastric banding (LAGB) is confounded by the greater weight loss after RYGB. We therefore examined the effect of these two surgeries on metabolic parameters matched on small and large amounts of weight loss.RESEARCH DESIGN AND METHODSSeverely obese individuals with type 2 diabetes were tested for glucose metabolism, β-cell function, and insulin sensitivity after oral and intravenous glucose stimuli, before and 1 year after RYGB and LAGB, and at 10% and 20% weight loss after each surgery.RESULTSRYGB resulted in greater glucagon-like peptide 1 release and incretin effect, compared with LAGB, at any level of weight loss. RYGB decreased glucose levels (120 min and area under the curve for glucose) more than LAGB at 10% weight loss. However, the improvement in glucose metabolism, the rate of diabetes remission and use of diabetes medications, insulin sensitivity, and β-cell function were similar after the two types of surgery after 20% equivalent weight loss.CONCLUSIONSAlthough RYGB retained its unique effect on incretins, the superiority of the effect of RYGB over that of LAGB on glucose metabolism, which is apparent after 10% weight loss, was attenuated after larger weight loss.

Impact of Gastric Banding Versus Metformin on β-Cell Function in Adults With Impaired Glucose Tolerance or Mild Type 2 Diabetes

“…Gastric banding (20)(21)(22) and metformin (23,24) have been shown to improve insulin sensitivity, b-cell function, and glycemia in people with fully developed T2D. In people with IGT or early, mild T2D, we observed no improvement in b-cell function and only modest improvements in glycemia despite large improvements in insulin sensitivity.…”

Metabolic surgery for the treatment of type 2 diabetes in patients with BMI lower than 35 kg/m2: Why caution is still needed

“…We mentioned above that the glycemic improvement of restrictive procedures versus RYGB in the SOS study was similar when the participants were matched by weight loss . The same results were seen in another study in which oral and intravenous glucose tolerance tests were performed after 10% and 20% weight loss in individuals after laparoscopic adjustable gastric banding and RYGB . Although individuals undergoing RYGB had a better glucose AUC after 10% weight loss, no difference between the procedures was observed at a more pronounced 20% weight loss, despite an increased incretin effect after RYGB.…”

“…34 The same results were seen in another study in which oral and intravenous glucose tolerance tests were performed after 10% and 20% weight loss in individuals after laparoscopic adjustable gastric banding and RYGB. 82 Although individuals undergoing RYGB had a better glucose AUC after 10% weight loss, no difference between the procedures was observed at a more pronounced 20% weight loss, despite an increased incretin effect after RYGB. Bradley et al found similar results when comparing the metabolic response, insulin sensitivity, and beta-cell function in response to a mixed meal in nondiabetics after a 20% weight loss with RYGB versus gastric banding, suggesting that weight loss was the most important driver of metabolic benefit.…”

Does obesity cause type 2 diabetes mellitus (T2DM)? Or is it the opposite?

“…It has some association with sensitivity in human subjects . HOMA insulin resistance (HOMA‐IR) in a type 2 diabetic group (BMI 41.8 kg/M 2 ) has been reported as 10.3 ± 7.7 while in an obese non‐diabetic group with a somewhat greater BMI (BMI 46.5 kg/M 2 ) HOMA‐IR was reported to be 5.8 ± 1.9 . The higher HOMA number in the diabetics with a lower BMI suggests greater insulin resistance in obese diabetics than is caused by the obesity.…”