Glucagon-like peptide-1 secretion in people with versus without type 2 diabetes: a systematic review and meta-analysis of cross-sectional studies

AIMS/HYPOTHESIS: The aim of this systematic review was to synthesise the study findings on whether GLP-1 secretion in response to a meal tolerance test is affected by the presence of type 2 diabetes (T2D). The influence of putative moderators such as age, sex, meal type, meal form, and assay type were also explored. METHODS: iAUC were extracted and used to calculate between-group standardised mean differences (SMD), which were meta-analysed using a random-effects model to derive pooled estimates of Hedges' g and 95 % prediction intervals (PI). RESULTS: ) was small and heterogenous between studies (g = 0.24, p = 0.21, PI: -1.55, 2.02). CONCLUSIONS: iAUC between individuals with, versus those without T2D were generally small and inconsistent between studies. Factors influencing study heterogeneity such as small sample sizes and poor matching of groups may help to explain the wide prediction intervals observed. Considerations to improve comparisons of GLP-1 secretion in T2D and potential mediating factors more important than T2D diagnosis per se are outlined. PROSPERO ID: CRD42020195612.