GLP-1 drugs increase residual food in the stomach but current evidence doesn't show a meaningful increase in aspiration events during surgery, questioning guidelines that recommend stopping these drugs pre-operatively.
4.8 vs. 4.6 per 10,000Aspiration rates were nearly identical between GLP-1 users and non-users in the largest retrospective study, despite higher residual gastric contents
What the researchers found
While GLP-1 receptor agonists do increase residual gastric contents (19-56% of users vs. 5-20% of non-users in 7 of 8 comparative studies), the available evidence does not show a significant increase in actual aspiration or regurgitation events. In three retrospective studies that specifically tracked aspiration events, one found nearly identical rates (4.8 vs. 4.6 per 10,000) and the other two found only one aspiration event in GLP-1 users versus none in controls.
Critically, the review found that nearly all studies had significant confounding factors — patients on GLP-1 drugs typically had diabetes, obesity, and other conditions that independently delay gastric emptying. The authors conclude that current societal guidelines recommending withholding GLP-1 drugs before surgery may not be well-supported by the available data.
Why it matters
Millions of people on GLP-1 drugs face surgery every year, and many medical societies have issued guidance to stop these medications days or weeks before procedures due to aspiration fears. This review challenges that approach by showing that while GLP-1 drugs do slow stomach emptying (as expected from their mechanism), the feared increase in aspiration events hasn't materialized in the data. This has direct implications for perioperative guidelines and patient safety protocols.
The numbers in context
3,712 citations screened · 24 studies included · 19-56% residual gastric contents in GLP-1 users vs. 5-20% in non-users · Aspiration rate: 4.8 vs. 4.6 per 10,000 · 6 GLP-1 drugs studied · All but 1 study had confounding factors
How the study worked
Librarian-assisted scoping review searching five electronic databases (PubMed, Embase, Web of Science, KCI, MEDLINE, Preprint Citation Index) from inception through March 2024. Included 24 studies (4 prospective, 6 retrospective, 5 case series, 9 case reports) evaluating residual gastric volume, retained food contents, regurgitation, and aspiration events in GLP-1 RA users. Two independent reviewers screened articles with systematic data extraction.
Who was studied
Patients using GLP-1 receptor agonists (semaglutide, liraglutide, tirzepatide, dulaglutide, exenatide, lixisenatide) undergoing procedures or evaluated for gastric contents
What this study cannot tell us
Most included studies had significant confounding factors (diabetes, other medications, comorbidities) that independently affect gastric emptying, making it difficult to isolate the GLP-1 effect. The evidence base is mostly observational with no RCTs. Case reports and case series (14 of 24 studies) provide low-quality evidence. The review covers studies through March 2024, so very recent data may not be included.
How to read the evidence
This is a well-conducted scoping review with systematic search methodology across five databases. However, the underlying evidence is predominantly observational with significant confounding. No RCTs exist on this specific question, and over half the included studies are case reports or case series.
When this study was published
Published in 2024 with literature search through March 2024. Highly current and directly relevant to ongoing debates about perioperative GLP-1 management.
The bigger picture
As GLP-1 drugs become among the most prescribed medications worldwide, their perioperative management is a pressing clinical question. Multiple major anesthesiology and surgical societies have published conflicting guidelines on whether to stop GLP-1 drugs before surgery. This review provides the most comprehensive look at the actual evidence, and its conclusion — that aspiration risk may be overstated — could influence future guideline revisions and prevent unnecessary medication interruptions.
Questions still open
- Should perioperative GLP-1 guidelines be revised given the lack of evidence for increased aspiration events?
- Would a large RCT comparing aspiration rates in GLP-1 users versus non-users definitively settle this debate?
- Is the risk-benefit calculation different for short-acting versus long-acting GLP-1 agonists before surgery?
Common questions
Should I stop my GLP-1 medication before surgery?
Why do GLP-1 drugs cause food to stay in the stomach longer?
Read the original research
A Scoping Review of GLP-1 Receptor Agonists: Are They Associated with Increased Gastric Contents, Regurgitation, and Aspiration Events?
Journal of clinical medicine, 13(21)
Citation
Chang, Marvin G; Ripoll, Juan G; Lopez, Ernesto; Krishnan, Kumar; Bittner, Edward A. (2024). A Scoping Review of GLP-1 Receptor Agonists: Are They Associated with Increased Gastric Contents, Regurgitation, and Aspiration Events?. Journal of clinical medicine, 13(21). https://doi.org/10.3390/jcm13216336