Study details and key findings

For the study, researchers analyzed data from 182 patients who received the GLP-1 drug semaglutide before undergoing bariatric surgery between 2017 and 2024. These patients were also matched to 182 controls who did not take semaglutide before undergoing bariatric surgery.

The average age of patients at surgery was 45 years, 77.5% were female, and 74% were white. Both groups had comparable baseline median weights and BMIs. Most of the patients underwent a sleeve gastrectomy, and around 10% underwent a Roux-en-Y gastric bypass.

According to the researchers, patients who took semaglutide for 24.4 weeks before their surgery lost a median of 4% of their body weight before the surgery took place. Including the preoperative weight loss, these patients had a greater combined total weight loss (22%) at three months after the operations compared to controls who did not take semaglutide (15%).

However, over time, the difference in weight loss between these two groups decreased. There were no significant differences in combined total weight loss at months six, nine, or 12. At month 12, the patients who received semaglutide had a combined total weight loss of 23% compared to 26% for patients who did not receive semaglutide.

"You might expect patients to lose more weight if they take a medication prior to surgery. But we were surprised to find that the group of patients who went on medicines first, and then had surgery, actually had the same combined total weight loss," said Eric Sheu, chief of the section of bariatric and foregut surgery at Brigham and Women's Hospital and one of the study's authors. "This contrasts with previous studies that have found that taking semaglutide after surgery can further help patients lose weight."

Commentary

Going forward, Sheu said the researchers will work on determining which weight-loss strategies are most effective for patients.

"We are trying to figure out the best timing for these strategies to maximize their effectiveness and safety. When a patient should start the medicine, when they should stop taking it before surgery, and when they should have the surgery are things that still need to be evaluated," Sheu said. "We also need to understand if the type of bariatric surgery matters for how patients respond to the medicines."

"We will need to conduct more research to answer the remaining questions, but there's at least a suggestion that the most effective weight-loss strategy isn't as simple as 1 + 1 = 2," he added. "The order of strategies may be key."

Advisory Board's weight-related resources

For more insights into GLP-1 drugs and other weight-related topics, check out these Advisory Board resources:

This expert insight outlines the five biggest questions about weight management drugs and their answers. Similarly, this expert insight addresses what headlines get wrong about weight management drugs and what healthcare leaders should know instead.

Radio Advisory's Rachel Woods has also covered GLP-1 drugs on the podcast, discussing the potential future of these drugs and how they could help — or hurt — health systems' finances. Other useful resources include this expert insight on the five catalysts that will impact the future of obesity care and this research on four key elements of comprehensive obesity care.

This emerging idea outlines how three health systems reinvented their weight management programs in order to provide comprehensive, high-quality obesity services. And this research can show you how stakeholder actions could shape three potential futures for obesity care and the strategies leaders can implement to ensure optimal outcomes.

Our weight management and obesity care resource library can also help leaders understand the current care landscape, manage innovations, and prepare for transformations in care.