Preoperative, postoperative GLP-1s improve weight loss in bariatric surgery patients

Editor's Note

Research shows using GLP-1 receptor agonists both before and after bariatric surgery is associated with greater total weight loss than surgery alone, according to a July 13 article in MedPage Today.

The article focuses on a retrospective analysis of 568 patients presented at ENDO 2025, the annual meeting of the Endocrine Society. All patients underwent sleeve gastrectomy or gastric bypass at Stanford Health Care between January 2019 and December 2023. It included 424 patients who had surgery alone, 21 who used a GLP-1 agent only in the two years prior, 68 who used one only in the two years after, and 47 who used a GLP-1 agent in both periods. The agents prescribed included semaglutide (Ozempic, Wegovy), tirzepatide (Mounjaro, Zepbound), liraglutide (Victoza, Saxenda), and dulaglutide (Trulicity). Patients had to be on the medication for at least four months to be included.

Findings show those who used GLP-1 agents in both periods saw a 33% total weight loss and a 17.9-point drop in BMI, compared with 30.3% and 14 points, respectively, in those who had surgery alone. Patients who used a GLP-1 agent only before surgery achieved a 29.7% weight loss and a 14.8-point BMI change, while those who used it only after surgery saw 30.7% weight loss and a 14.4-point BMI change. These single-period approaches did not lead to greater weight loss than surgery alone, researchers noted.

As detailed in the article, patients taking a GLP-1 agent during the perioperative period had higher preoperative BMIs (49.4 vs 45.7) and higher rates of comorbidities, including type 2 diabetes (53.7% vs 26.2%), hypertension (62.5% vs 46.9%), gastroesophageal reflux disease (69.9% vs 59.9%), and cerebrovascular disease (5.2% vs 1.4%).

Limitations of the study reportedly include the small sample size in the preoperative-only group and limited access to higher-dose regimens due to insurance and availability. She also acknowledged that earlier agents such as liraglutide and dulaglutide may have diluted the weight-loss effect compared to newer drugs.