Association between hemoglobin A1C response to glucagon-like peptide-1 receptor agonists and hemoglobin A1C and weight outcomes post-bariatric surgery

Abstract

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are a common treatment for type 2 diabetes mellitus (T2D). Endogenous glucagon-like peptide-1 secretion is a proposed mediator of T2D remission following bariatric surgery. We evaluated the association between preoperative response to GLP-1RAs and T2D outcomes following bariatric surgery. Our institution's bariatric surgery database was queried for patients with T2D who had taken a GLP-1RA prior to Roux-en-Y gastric bypass (N = 38) or vertical sleeve gastrectomy (N = 9). Response to GLP-1RAs was defined as change in hemoglobin A1C from initiation of therapy to ∼6 months. Postoperative outcomes included A1C and weight loss at 6 months (N = 44), 1 year (N = 44) and 2 years (N = 38) following surgery. The association between GLP-1RA response and postoperative outcomes was evaluated using multivariable generalized linear mixed models adjusted for postoperative time point, A1C prior to initiation of GLP-1RA, weight and surgery type. Mean A1C at initiation of therapy was 8.3 ± 1.4% and decreased by 1.1 ± 1.5% on GLP-1RA treatment. Greater response to GLP-1RA adjusted for initial A1C was correlated with reduced A1C at 6 months (r = 0.38, p = 0.02) and 2 years (r = 0.42, p = 0.03) but not weight loss following bariatric surgery. Every 1% decrease in A1C on GLP-1RA was associated with 0.30 ± 0.10% reduction in postoperative A1C and doubled odds of normoglycemia with A1C<5.7% (odds ratio: 2.00, 95% confidence interval: 1.12–3.45). Our findings offer preliminary evidence for a potential use of GLP-1RAs in predicting glycemic outcomes following bariatric surgery in patients with T2D. Further studies are needed to continue investigating this relationship. • GLP-1 is a potential mediator of post-bariatric surgery diabetes remission. • Preoperative GLP-1R agonist response is associated with A1C reduction post-bariatric surgery. • No association between GLP-1R agonist response and postoperative weight loss was found. • GLP-1R agonist response may be a predictor of diabetes remission following surgery.