1128 Effect of Sleeve Gastrectomy on Ghrelin, GLP-1, PYY, and GIP Gut Hormones: A Systematic Review and Meta-Analysis

Abstract

INTRODUCTION: Despite sleeve gastrectomy becoming the most common surgical weight loss procedure, weight loss mechanisms remain less clear. The primary aim of this study was to perform a structured systematic review and meta-analysis of all eligible studies to evaluate changes in various gut hormone levels in patients following sleeve gastrectomy. METHODS: Searches of PubMed, EMBASE, Web of Science, and the Cochrane Library databases were performed through April 1, 2019 in accordance with PRISMA and MOOSE guidelines. Measured outcomes included pre- and post-operative hormones: fasting ghrelin, post-prandial glucagon-like peptide-1 (GLP-1), post-prandial peptide YY (PYY), and fasting gastric inhibitory peptide (GIP) levels. Hedge’s g was used to determine pooled effect size and corresponding 95% confidence intervals (CIs). Heterogeneity was assessed with Cochran Q test and I 2 statistics. Study quality was evaluated with the Newcastle-Ottawa Quality Assessment Scale (NOS) score for observational studies and JADAD score for randomized controlled trials. Publication bias was evaluated by funnel plot using Egger and Begg tests. RESULTS: A total of 28 studies (n = 653; 29.56% male) were included. Mean age was 42.00 ± 5.48 years with average follow-up of 11.70 ± 11.38 months. Pre-procedure BMI was 46.01 ± 4.07 kg/m2 with a post-sleeve gastrectomy BMI of 34.07 ± 3.73 kg/m2 (%EWL 57.48 ± 9.64). Ghrelin decreased [Hedge’s g of -1.486 (95% CI, -1.884 to -1.089); I 2 = 91.95%; Q-value of 310.57] while GLP-1 and PYY increased post-procedure [Hedge’s g of 1.095 (95% CI, 0.509 to 1.642); I 2 = 84.38%; Q-value of 70.43) and Hedge’s g of 1.396 (95% CI, 0.781 to 2.011); I 2 = 84.02%; Q-value of 62.59), respectively]. GIP did not significantly change [Hedge’s g of -0.213 (95% CI, -1.019 to 0.592; I 2 = 79.65%; Q-value of 4.92]. Baseline characteristics as stratified by individual gut hormone are shown in Table 1. Quality assessment revealed all studies to be of high quality (i.e., NOS score ≥4 or JADAD score of ≥3). Classic fail-safe determined it would take 2044, 244, and 248 non-significant studies to nullify the difference in gut hormone levels for ghrelin, GLP-1, and PYY, respectively. CONCLUSION: Ghrelin levels decrease while post-prandial GLP-1 and PYY increase after sleeve gastrectomy. GIP levels remain unchanged. Future studies are needed to assess the role of these gut hormones and relationship to weight loss and metabolic outcomes. These results may have the potential to optimize patient selection in an era personalized medicine.