Glucose control is initially superior following Roux-en-Y gastric bypass (RYGB), as compared with laparoscopic adjustable gastric banding (LAGB), but the effect is not sustained beyond 10% weight loss, according to a study published in Diabetes Care.1

Marlena M. Holter, of the New York Obesity Nutrition Center and Columbia University College of Physicians and Surgeons, and colleagues studied the influence of weight loss vs altered nutrient route to improvement in beta-cell function on incretin effect, beta-cell sensitivity, and insulin sensitivity following either RYGB or LAGB. The study included 61 people with severe obesity and type 2 diabetes who were scheduled for either RYGB or LAGB at Mount Sinai St. Luke’s Hospital.

Study participants were assessed before and 1 year after surgery, as well as at 10% and 20% matched weight loss.


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At 1 year, RYGB (n=27) resulted in almost twice the amount of weight loss compared with LABG (n=12; 30.1% vs 16.6%).1 Regardless of weight loss, however, decrease in diabetes medication use was similar between groups, as was the percentage of patients in both groups experiencing diabetes remission (RYGB, 88% and LAGB, 83%).1

Glucagon-like peptide 1 (GLP-1) release and incretin effect were greater with RYGB, compared with LAGB, at any level of weight loss,1 according to the data. Additionally, at 10% weight loss, improvements in glucose levels were also superior with RYGB.1 At 20% weight loss, however, the 2 surgical procedures were comparable for most metabolic parameters, including glucose metabolism, insulin sensitivity, beta-cell function, the rate of diabetes remission, and use of diabetes medications.1

Weight loss within the RYGB group occurred about twice as quickly as in the LAGB group for both 10% weight loss (4.2 ± 0.9 vs 8.7 ± 8.5 weeks; P =.020) and 20% weight loss (median time: 26.2 vs 54.5 weeks), respectively.1

“Our study confirms that surgical weight loss is a very effective mode to achieve glucose control in severely obese individuals with type 2 diabetes,” study researcher Blandine Laferrère, MD, also from the New York Obesity Nutrition Center and Columbia University College of Physicians and Surgeons, told Endocrinology Advisor. “Weight loss after bariatric surgery is substantial—16% to30%—and can be achieved with RYGB and with adjustable gastric banding, although RYGB is more effective at achieving larger weight loss.”

This study was limited by the lack of randomization of the 2 surgical procedures, as procedure was selected based on preference of patient and surgeon, lack of controlled diet, variability in the time it took for patients who underwent LAGB to lose weight compared with RYGB, and the shortcomings of the methods used to determine beta-cell function. Additionally, considerably fewer patients who underwent LAGB completed all study visits compared with their counterparts, particularly those achieving 20% weight loss, which may have underpowered study results. The researchers pointed out that weight loss after LAGB is typically less than that achieved by participants in this study. 

Previous studies2-4 have demonstrated the efficacy of surgical weight loss, and RYGB in particular, in controlling type 2 diabetes. The resultant improvement in the effect of incretin gut hormones is usually credited with playing a large part in diabetes remission following surgery, regardless of weight loss.5 Typically, the improvement in glucose control after RYGB vs LAGB is confounded by the greater weight loss associated with RYGB.

While the data from the present study confirm incretin involvement in diabetes remission, Dr Laferrère noted that “[t]he ‘special effect’ of RYGB on incretin levels and glucose-lowering may contribute only minimally to the overall glucose control and diabetes remission. If patients can lose large amounts of weight after adjustable gastric banding, they seem to have similar improvement of their insulin sensitivity and secretion, in spite of the enhanced incretin release observed uniquely after RYGB.”

Disclosures: The researchers report no relevant conflicts of interest.

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References

  1. Holter MM, Dutia R, Stano SM, et al. Glucose metabolism after gastric banding and gastric bypass in individuals with type 2 diabetes: weight loss effect. Diabetes Care. 2016 Nov 8. doi:10.2337/dc16-1376 [Epub ahead of print].
  2. Schauer PR, Bhatt DL, Kirwan JP, et al. STAMPEDE Investigators. Bariatric surgery versus intensive medical therapy for diabetesd3-year outcomes. N Engl J Med. 2014;370:2002-2013.
  3. Mingrone G, Panunzi S, De Gaetano A, et al. Bariatric surgery versus conventional medical therapy for type 2 diabetes. N Engl J Med. 2012;366:1577–1585.
  4. Courcoulas AP, Belle SH, Neiberg RH, et al. Three-year outcomes of bariatric surgery vs life- style intervention for type 2 diabetes mellitus treatment: a randomized clinical trial. JAMA Surg. 2015;150:931–940.
  5. Laferrère B. Diabetes remission after bariatric surgery: is it just the incretins? Int J Obes (Lond). 2011;35(suppl 3):S22-S25.