A Meta-Analysis of GLP-1 After Roux-En-Y Gastric Bypass: Impact of Surgical Technique and Measurement Strategy

Obes Surg. 2018 Mar;28(3):615-626. doi: 10.1007/s11695-017-2913-1.


Background: Roux-en-Y gastric bypass (RYGB) is an effective treatment for diabetes. Glucagon-like peptide-1 (GLP-1) is a gut hormone that is important to glucose homeostasis.

Objective: This study aimed to assess GLP-1 level and its predictors after RYGB.

Methods: The study design was a meta-analysis. The data sources were MEDLINE, EMBASE, Web of Science, and the Cochrane Databases. The study selection composed of studies with pre- and post-RYGB levels. The main outcomes were as follows: Primary outcome was the change in postprandial GLP-1 levels after RYGB. Secondary outcomes included the changes in fasting glucose, fasting insulin, and fasting GLP-1 levels after RYGB. Meta-regression to determine predictors of changes in GLP-1 levels was performed. Outcomes were reported using Hedge's g.

Results: Twenty-four studies with 368 patients were included. Postprandial GLP-1 levels increased after RYGB (Hedge's g = 1.29, p < 0.0001), while fasting GLP-1 did not change (p = 0.23). Peak postprandial GLP-1 levels gave the most consistent results (I 2 = 9.11). Fasting glucose and insulin levels decreased after RYGB (p < 0.0001). Roux limb length was a significant predictor for amount of GLP-1 increase (β = - 0.01, p = 0.02). Diabetes status, amount of weight loss, length of biliopancreatic limb, and time of measurement were not significant predictors (p > 0.05).

Conclusion: Postprandial GLP-1 levels increase after RYGB, while fasting levels remain unchanged. Shorter Roux limb length is associated with greater increase in postprandial GLP-1, which may lead to better glycemic control in this population.

Keywords: Bariatric; Diabetes; GLP-1; Incretin; Mechanism; Metabolic; Obesity; RYGB.

Publication types

  • Meta-Analysis
  • Review

MeSH terms

  • Blood Glucose / analysis
  • Blood Glucose / metabolism
  • Fasting / blood
  • Gastric Bypass / methods*
  • Gastric Bypass / rehabilitation*
  • Gastrointestinal Hormones / blood
  • Glucagon-Like Peptide 1 / analysis
  • Glucagon-Like Peptide 1 / blood*
  • Humans
  • Insulin / blood
  • Insulin Resistance
  • Obesity, Morbid / blood
  • Obesity, Morbid / surgery*
  • Postprandial Period
  • Treatment Outcome
  • Weight Loss / physiology


  • Blood Glucose
  • Gastrointestinal Hormones
  • Insulin
  • Glucagon-Like Peptide 1