Improvement in glucose metabolism after bariatric surgery: comparison of laparoscopic Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy: a prospective randomized trial

Ann Surg. 2009 Aug;250(2):234-41. doi: 10.1097/SLA.0b013e3181ae32e3.


Background: The exclusion of the proximal small intestine is thought to play a major role in the rapid improvement in the metabolic control of diabetes after gastric bypass.

Objective: In this randomized, prospective, parallel group study, we sought to evaluate and compare the effects of laparoscopic Roux-en-Y gastric bypass (LRYGB) with those of laparoscopic sleeve gastrectomy (LSG) on fasting, and meal-stimulated insulin, glucose, and glucagon-like peptide-1 (GLP-1) levels.

Methods: Thirteen patients were randomized to LRYGB and 14 patients to LSG. The mostly nondiabetic patients were evaluated before, and 1 week and 3 months after surgery. A standard test meal was given after an overnight fast, and blood samples were collected before and after food intake in both groups for insulin, GLP-1, glucose, PYY, and ghrelin concentrations. This trial was registered in (NCT00356213) before the first patient was randomized.

Results: Body weight and body mass index decreased markedly (P < 0.002) and comparably after either procedure. Excess BMI loss was similar at 3 months (43.3 +/- 12.1% vs. 39.4 +/- 9.4%, P > 0.36). After surgery, patients had markedly increased postprandial plasma insulin and GLP-1 levels, respectively (P < 0.01) after both of these surgical procedures, which favor improved glucose homeostasis. Compared with LSG, LRYGB patients had early and augmented insulin responses as early as 1-week postoperative; potentially mediating improved early glycemic control. After 3 months, no significant difference was observed with respect to insulin and GLP-1 secretion between the 2 procedures.

Conclusion: Both procedures markedly improved glucose homeostasis: insulin, GLP-1, and PYY levels increased similarly after either procedure. Our results do not support the idea that the proximal small intestine mediates the improvement in glucose homeostasis.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Glucose / metabolism*
  • Body Mass Index
  • Cohort Studies
  • Female
  • Gastrectomy*
  • Gastric Bypass*
  • Ghrelin / blood
  • Glucagon-Like Peptide 1 / blood
  • Humans
  • Insulin / blood
  • Laparoscopy*
  • Male
  • Middle Aged
  • Obesity, Morbid / complications
  • Obesity, Morbid / metabolism*
  • Obesity, Morbid / surgery*
  • Young Adult


  • Blood Glucose
  • Ghrelin
  • Insulin
  • Glucagon-Like Peptide 1

Associated data