Preoperative GLP-1 Receptor Agonist Use and Weight Loss Outcomes Following Bariatric Surgery

OBJECTIVE: Evaluate associations between preoperative glucagon-like peptide-1 receptor agonist (GLP-1) use and postoperative weight loss after metabolic and bariatric surgery (MBS). SUMMARY BACKGROUND DATA: Recent literature suggests reduced postoperative weight loss following preoperative GLP-1 use. However, these single center studies suffered from key design limitations. METHODS: This retrospective cohort study utilized a statewide health information exchange enrolling adults undergoing MBS from 2020-2024. In the primary analysis, patients with ≥1 GLP-1 order in the 6 months preoperatively were compared with those with none. In a subgroup analysis of patients with type 2 diabetes, preoperative GLP-1 therapy was compared with non-GLP-1 antihyperglycemic therapy. Outcomes included BMI trajectory from 12 months pre- through 12 months postoperatively and percent total weight loss (%TWL) at 3, 6, 9, and 12 months. Associations were estimated using multivariable linear mixed-effects models. RESULTS: Among 2,379 MBS patients, 193 (8.1%) had preoperative GLP-1 exposure. Adjusted BMI was higher for GLP-1 users 12 months pre-op (47.0 vs. 44.4 kg/m²; P<0.001) but similar at surgery (45.9 vs. 46.1; P=0.81). Postoperative BMI and %TWL trajectories were similar through 12 months (GLP-1 users %TWL 20.7% vs. 22.0% nonusers, P=0.19). In the diabetes cohort (n=256; 149 GLP-1, 107 active comparators), trajectories were also similar (GLP-1%TWL 21.5% vs. 23.1% active comparators, P=0.39). CONCLUSIONS: Preoperative GLP-1 use was not associated with postoperative weight loss in a statewide, multi-system cohort, including in an active-comparator analysis among patients with type 2 diabetes. These findings suggest preoperative GLP-1 therapy is unlikely to compromise MBS weight loss outcomes.