GLP-1 Receptor Agonists Versus Bariatric Surgery: Effects of Weight Loss and BMI on Subsequent General Surgical...

Obesity and T2DM substantially increase postoperative risk, with higher surgical site infections in obesity and up to a 65% increase in overall complications in T2DM. This study assesses the impact of weight loss interventions-metabolic bariatric surgery (MBS) and glucagon-like peptide-1 receptor agonists (GLP-1RA)-on BMI reduction and how that translates to postoperative outcomes in general surgery patients. Patients undergoing general surgery (2016-2024) were identified in the Epic Cosmos database. GLP-1RA or MBS exposure occurred 1-3 years preoperatively (GLP-1RA coverage ≥ 80%). Entropy balancing produced weighted cohorts with similar baseline profiles, followed by multivariable regression models assessing the association between weight loss intervention and BMI change, and the impact of BMI on postoperative outcomes. Overall 9470 individuals underwent a general surgery procedure. Median patient age was 64, with mostly females (60.6%). More patients received GLP-1RA (n = 7823, 82.3%) than MBS (n = 1647, 17.4%). MBS patients had higher initial BMIs (≥ 40: 60.8% vs. 24.5%, p < 0.001). MBS led to greater BMI reduction than GLP-1RA (Mean difference: -9.89, 95% CI: -9.64, -10.34). Higher BMI at time of a general surgical procedure correlated with increased postoperative complications (OR: 1.01, 95% CI: 1.00-1.01) and extended LOS (OR: 1.01, 95% CI: 1.00-1.01). MBS was associated with lower complication odds (OR: 0.87, 95% CI: 0.78-0.98). MBS improved surgical outcomes in patients with obesity and T2DM through greater BMI reduction compared with GLP-1RAs. These findings support the role of preoperative weight loss to mitigate surgical risk; however, evaluating outcomes relative to no intervention remains an important future direction.