HSS Studies Contribute Early Evidence to Help Guide Emerging Perioperative Considerations for Patients Using GLP 1 Medications

At this year's American Society of Regional Anesthesia and Pain Medicine (ASRA) annual meeting, researchers at Hospital for Special Surgery (HSS) presented two studies focused on glucagon-like peptide-1 (GLP-1) agonist usage in patients undergoing surgery. GLP-1 agonists are a class of medications commonly prescribed to treat type 2 diabetes and obesity, and their therapeutic potential is extending to a range of conditions including cardiovascular and neurodegenerative diseases. These studies highlight the need for clear, evidence-based guidance as the use of GLP-1s expands.

"As GLP-1 medications increase in popularity, the effect of these drugs in patients undergoing surgery raises concerns for anesthesiologists," says Oliver PF Panzer, MD, anesthesiologist at HSS and author of both studies. "We seek to better understand the usage and impact of GLP-1s on patients undergoing surgery so we can adapt the management of these patients to maximize their safety."

Study: Cross Sectional Assessment of Preoperative Gastric Content with Ultrasound in Patients Taking GLP-1 Agonists

In the study "Cross Sectional Assessment of Preoperative Gastric Content with Ultrasound in Patients Taking GLP-1 Agonists," researchers set out to explore how GLP-1 medications affect gastric emptying in patients scheduled for surgery. Food retained in the stomach can increase the risk of regurgitation and pulmonary aspiration of gastric contents, a serious, life-threatening complication during general anesthesia.

"Previous studies show patients using the GLP-1 agonist semaglutide (Ozempic, Wegovy, and Rybelsus) experience slower gastric emptying, which can result in residual gastric contents even when these patients follow standard preoperative fasting guidelines," says Dr. Panzer. "We became concerned that patients taking GLP-1s may not be adequately protected from aspiration during anesthesia under the current guidelines."

"The goal of this study was to look at the incidence of full stomach in patients taking GLP-1s compared to patients not taking the drugs," says Dr. Panzer. "We also wanted to look at fasting times to detect whether people on GLP-1s who fast longer than the guidelines recommend trend toward being less full."

In the multi-center, prospective, cross-sectional observational study, researchers used ultrasound to assess the preoperative incidence of full stomach in elective surgery patients taking weekly injectable GLP-1s compared to elective surgery patients not taking the drugs. A total of 354 patients were included in the study between August 29, 2023, and January 31, 2025. Ultrasound was performed by an anesthesiologist in the preoperative holding area, with clear fluid >1.5ml/kg or solid content indicating a full stomach. All institutions followed American Society of Anesthesiology "nothing by mouth" (NPO) fasting guidance (8 hours for heavy fatty foods; 6 hours for light meals; 2 hours for clear liquids).

Dr. Panzer and colleagues found no significant difference in the incidence of full stomach between patients taking GLP-1s and those who do not. Overall fasting times for solids tended to be longer in full patients in the GLP-1 group compared to the control group (23.73 vs 16.63 hours) but did not reach statistical significance.

"This multicenter study showed no difference in the rate of full stomachs between the GLP-1 group and the control group, which stands in contrast to what most studies have shown so far," says Dr. Panzer. "One possible explanation for our result is that our patients report higher average fasting times (18.5 hours) than patients at other institutions. However, there may be other factors that warrant further investigation."

"We hope to follow up this study with research that examines whether 24 hours of solid food fasting is helpful in reducing full stomach in patients on GLP-1s," says Dr. Panzer. "Another question is whether pausing GLP-1s prior to surgery may have an impact on full stomach. Although the current guidance says to continue taking GLP-1s before surgery because stopping the drug poses its own health risks, it's a question worth exploring."

Study: Institutional Trends in GLP-1 Agonist Use Among Hip and Knee Arthroplasty Patients, 2021-2024

In the study, "Institutional Trends in Glucagon-Like Peptide-1 Receptor Agonist Use Among Hip and Knee Arthroplasty Patients, 2021-2024," researchers explore the prevalence of glucagon-like peptide-1 (GLP-1) agonist use among patients undergoing primary and revision total hip arthroplasty (THA) and total knee arthroplasty (TKA) at HSS.

"As usage of GLP-1s continues to expand in the general population, we wanted to capture the incidence and type of GLP-1 usage among patients undergoing hip and knee arthroplasty," says Dr. Panzer.

The researchers retrospectively reviewed the records of 45,537 adult patients who underwent primary or revision THA or TKA between January 4, 2021, and December 31, 2024. Dr. Panzer and colleagues found GLP-1 use increased significantly in that period, rising from 3.69% in 2021 to 12.84% in 2024. Semaglutide and tirzepatide were the most common agents, accounting for 88% of all GLP-1 use in 2024. Higher rates of GLP-1 use were seen in patients with significant comorbidities such as hypertension, diabetes, or heart failure, and in Black patients.

"We also saw a significant decrease in the number of GLP-1 users with diabetes in this time period, suggesting that more patients are using these medications for other reasons such as weight loss," notes Dr. Panzer.

"We will continue to examine GLP-1 usage in the surgical orthopedic population so we can ensure patients on these drugs can have surgery safely," says Dr. Panzer. "We're just at the beginning of this investigative journey, so there is a lot more insight to come."

These studies contribute important early evidence to help guide emerging perioperative considerations for patients using GLP-1 medications.

References:

Study 1: Cross Sectional Assessment of Preoperative Gastric Content with Ultrasound in Patients Taking GLP-1 Agonists

Authors: Oliver Panzer, Maya Tailor, Juliet E. Rowe, Michael Singleton, William Manson, Hari Kalagara, Nibras Bughrara, Anahita Dabo-Trubelja, Marissa Weber, Eric Heinz, Stephen C. Haskins, William P. Qiao, Miriam Sheetz, Alex Illescas, Kayla Bernstein, Mariel Maramba, Mahtab Sheikh, Jayanta Chowdhury, Sheila Carr, Tatum Gee, Eduard Shaykhinurov, Justas Lauzadis, Jashvant Poeran, Anahi Perlas

Study 2: Institutional Trends in Glucagon-Like Peptide-1 Receptor Agonist Use Among Hip and Knee Arthroplasty Patients, 2021-2024

Authors: Juliet Rowe, Maya Tailor, Alexandra Sideris, Alex Illescas, Jawad Saleh, Jashvant Poeran, Daniel Maalouf, Oliver Panzer