Review finds uncertain benefit from GLP‑1 use before bariatric surgery

What happened

A systematic review examined whether using a GLP-1 receptor agonist before metabolic or bariatric surgery changes perioperative outcomes. Ten studies with 5,461 participants were included. The pooled evidence suggested some weight reduction before surgery, but did not show a clear improvement in weight loss after the operation or in the other assessed outcomes.

The review queried three literature indexes. They were PubMed, Embase, and Web of Science. Coverage extended from each index's start through September 2025. The main measures were weight change before the operation and the share of total body weight lost afterward. Complications, HbA1c, and diabetes remission were secondary measures.

Across the included reports, the median presurgical reduction was 4.87 kg for GLP-1 users versus 3.84 kg for comparators. The abstract calls the reduction moderate. Its accompanying statistics are difficult to reconcile: standardized mean difference 0.40, 95% CI -0.37 to 1.18, and P below .01. Since the confidence limits cross zero, the abstract alone cannot establish the size or certainty of this effect.

The authors did not find a significant improvement in postoperative total weight loss percentage. For complications, the risk ratio was 1.62 and the 95% CI was 0.76 to 3.45, another statistically inconclusive result. Assessed comorbidity outcomes did not show significant improvement.

What it means

Some patients arrive at a bariatric program already using a GLP-1 medicine, while others may be offered medication during surgical preparation. This review suggests that such use can coincide with a modest amount of presurgical weight reduction. It does not establish a durable advantage after the operation.

The wide complication interval is important. The pooled estimate is compatible with lower risk, little difference, or a meaningful increase. The analysis therefore does not prove either added danger or equivalent safety across all operations, drugs, doses, and patient groups.

What it does not mean

This review does not provide a universal instruction to start, continue, pause, or discontinue a GLP-1 medicine before anesthesia. Those decisions can depend on the drug, dosing schedule, symptoms, diabetes control, procedure, and the current plan from the anesthesia and surgical teams.

The findings do not show that medication before surgery replaces bariatric surgery or that it improves long-term postoperative results. The included studies were not one large randomized trial using a single protocol. Differences among the component studies can limit what a pooled estimate says about an individual.

The internal inconsistency in the abstract's preoperative result is another reason for restraint. Until the calculation and reporting are resolved from the full analysis, the safest summary is that the review suggests modest presurgical weight reduction while leaving the magnitude uncertain.