GLP-1 use before bariatric surgery

A retrospective US database study published in The American Journal of Medicine examined whether adults who had used a GLP-1 receptor agonist or tirzepatide before metabolic and bariatric surgery had different early cardiovascular and kidney outcomes than matched nonusers. Over the 90 days after surgery, prior use was associated with lower observed rates of a four-part major adverse cardiovascular event outcome and postoperative kidney events^[1]. It is an association from medical records, not proof that a medicine caused the difference.

The study raises a useful question about the period before surgery, but it does not establish a treatment plan for any individual. For background on the drug class, see the tirzepatide overview and the semaglutide overview. Decisions around surgery, diabetes, kidney disease, and cardiovascular risk require an individual clinical assessment.

What the study compared

Researchers used the US Medical Records Database to identify adults who underwent metabolic and bariatric surgery from 2016 through 2025. The prior-use group had at least one prescription for a GLP-1 receptor agonist or tirzepatide between 365 and 7 days before surgery. People with a prescription closer to surgery were excluded, so the paper does not evaluate medication use immediately before an operation^[1].

The authors matched prior users and nonusers one-to-one with propensity scores. After matching, each group contained 11,052 people and the measured baseline characteristics were described as well balanced^[1]. Matching can make the compared groups more alike on recorded factors, yet it cannot account for factors absent from the database or measured imperfectly.

The exposure combines several GLP-1 receptor agonists with tirzepatide rather than testing one named product against another. Readers looking for a class-level orientation can use the semaglutide reference page, while the tirzepatide reference page describes the related dual incretin medicine. This study cannot separate their effects.

What happened in the first 90 days

The primary outcome was four-point major adverse cardiovascular events, abbreviated as MACE. The abstract reports events in 36 prior users, or 0.3%, compared with 67 nonusers, or 0.6%. Researchers estimated a hazard ratio of 0.535 with a 95% confidence interval from 0.357 to 0.803^[1]. In this matched cohort, that estimate is compatible with a lower observed event rate among prior users during the defined follow-up window.

Early postoperative kidney events were a key secondary outcome. They occurred in 158 prior users, or 1.4%, and 256 nonusers, or 2.3%; the reported hazard ratio was 0.613 with a 95% confidence interval from 0.502 to 0.747^[1]. The paper also reported lower observed risks of coronary events and heart failure among prior users. The abstract does not establish why those differences appeared.

These percentages describe the study population, its definitions, and a 90-day period after surgery. They should not be read as a personal forecast. Baseline illness, the type of surgery, medication history, perioperative care, and data-recording practices may all affect how closely a person's situation resembles the cohort. The tirzepatide overview and semaglutide overview offer general context, not a way to estimate surgical risk.

Why the result cannot prove cause and effect

This was a retrospective cohort study, which means the researchers looked back at records rather than assigning people to medicines at random. Propensity-score matching addresses some measured differences between groups, but it cannot remove residual confounding. For example, factors related to access to care, clinician selection, changes in metabolic health, or preparation for surgery may not be fully captured in the records^[1].

The exposure definition also matters. A prior prescription is not a complete record of use, adherence, treatment duration, or the reason a medicine was selected. It did not compare a standardized preoperative strategy with an alternative strategy, and it did not report a randomized test of continuing, stopping, or starting a medicine near surgery. Those questions need prospective research designed specifically to answer them.

The combined exposure makes the finding relevant to a broader incretin-treatment question, but it limits drug-specific interpretation. The semaglutide reference page and tirzepatide reference page identify different medicines; neither page changes the limits of this study's design.

What this means for readers considering surgery

The paper supplies an early observational signal worth discussing in research and clinical settings. It does not show that prior GLP-1 receptor agonist or tirzepatide use makes surgery safer, nor does it establish a universal preoperative approach. A lower association in a matched database is different from a demonstrated reduction in risk caused by a specific intervention.

People preparing for metabolic and bariatric surgery may have questions about their current medicines, cardiovascular history, diabetes, hydration, or kidney function. Those questions are best directed to the surgical and prescribing teams that know the person's history. The tirzepatide overview and semaglutide overview can help readers recognize the terms used in the study, but they are educational resources rather than individualized medical guidance.

Future work would need to distinguish individual medicines, document timing and exposure more precisely, and test whether a defined perioperative strategy changes outcomes. Until then, the appropriate conclusion is narrow: in this retrospective matched cohort, prior use was associated with lower recorded 90-day cardiorenal events after metabolic and bariatric surgery.

This article is for educational purposes only and does not constitute medical advice. Consult a qualified healthcare provider before making treatment or surgical decisions.