Study wrapper · #138
Real-World Effectiveness of Semaglutide and Tirzepatide Compared With Bariatric Surgery.
Editor's note
A large retrospective real-world cohort (44,025 adults, BMI >=35, two urban health systems, 2018 to 2024) comparing weight loss on injectable semaglutide or tirzepatide against sleeve gastrectomy and gastric bypass, using inverse-probability weighting to balance groups. Researchers found bariatric surgery was associated with substantially greater total weight loss at 1 to 3 years: for example roughly 22 to 28% with surgery versus about 7 to 9% (semaglutide) and 11 to 12% (tirzepatide) in the per-protocol analysis. Tirzepatide outperformed semaglutide. Key caveats: this is observational, so residual confounding by indication remains despite weighting; medication adherence is imperfect (intention-to-treat numbers ran below per-protocol); and real-world dosing and persistence differ from trials. Weight it as a useful real-world magnitude comparison, not a randomized head-to-head. It reflects effectiveness as actually used, which for the drugs runs below the results seen in controlled trials.
Plain-language abstract
This study used medical records from two city health systems to compare how much weight people lost with weekly injectable semaglutide or tirzepatide versus two weight-loss operations, sleeve gastrectomy and gastric bypass. It included 44,025 adults with a BMI of at least 35, treated between 2018 and 2024, and used statistical methods to make the groups more comparable. Over 1 to 3 years, surgery was linked to much greater weight loss: about 22% to 28% of body weight with the operations, compared with roughly 7% to 9% with semaglutide and about 11% to 12% with tirzepatide. Tirzepatide led to more weight loss than semaglutide. Because this is a look-back study rather than a randomized trial, differences between people who chose surgery versus medication could affect the results, and people do not always keep taking the drugs. The authors conclude that, among patients eligible for both, surgery was associated with greater weight loss.