Secretion of glucagon-like peptide-1 in patients with type 2 diabetes mellitus: systematic review and meta-analyses of clinical studies

Diabetologia. 2013 May;56(5):965-72. doi: 10.1007/s00125-013-2841-0. Epub 2013 Feb 3.


Aims/hypothesis: We carried out a systematic review of clinical studies investigating glucagon-like peptide-1 (GLP-1) secretion in patients with type 2 diabetes and non-diabetic controls and performed meta-analyses of plasma total GLP-1 concentrations during an OGTT and/or meal test.

Methods: Random effects models for the primary meta-analysis and random effects meta-regression, subgroup and regression analyses were applied.

Results: Random effects meta-analysis of GLP-1 responses in 22 trials during 29 different stimulation tests showed that patients with type 2 diabetes (n = 275) and controls without type 2 diabetes (n = 279) exhibited similar responses of total GLP-1 (p = NS) as evaluated from peak plasma concentrations (weighted mean difference [95% CI] 1.09 pmol/l [-2.50, 4.67]), total AUC (tAUC) (159 pmol/l × min [-270, 589]), time-corrected tAUC (tAUC min⁻¹) (0.99 pmol/l [-1.28, 3.27]), incremental AUC (iAUC) (-122 pmol/l × min [-410, 165]) and time-corrected iAUC (iAUC min⁻¹) (-0.49 pmol/l [-2.16, 1.17]). Fixed effects meta-analysis revealed higher peak plasma GLP-1 concentrations in patients with type 2 diabetes. Subgroup analysis showed increased responses after a liquid mixed meal test (peak, tAUC and tAUC min⁻¹) and after a 50 g OGTT (AUC and tAUC min⁻¹), and reduced responses after a solid mixed meal test (tAUC min⁻¹) among patients with type 2 diabetes. Meta-regression analyses showed that HbA1c and fasting plasma glucose predicted the outcomes iAUC and iAUC min⁻¹, respectively.

Conclusions/interpretation: The present analysis suggests that patients with type 2 diabetes, in general, do not exhibit reduced GLP-1 secretion in response to an OGTT or meal test, and that deteriorating glycaemic control may be associated with reduced GLP-1 secretion.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / metabolism*
  • Diabetes Mellitus, Type 2 / physiopathology
  • Down-Regulation
  • Enteroendocrine Cells / metabolism
  • Glucagon-Like Peptide 1 / blood
  • Glucagon-Like Peptide 1 / metabolism*
  • Glucose Tolerance Test
  • Glycated Hemoglobin A / analysis
  • Humans
  • Hyperglycemia / etiology
  • Intestinal Mucosa / metabolism*
  • Postprandial Period
  • Severity of Illness Index


  • Glycated Hemoglobin A
  • hemoglobin A1c protein, human
  • Glucagon-Like Peptide 1