The ever-accelerating usage of glucagon-like peptide-1 (GLP-1) agonists among the general population is impacting perioperative teams that are concerned about patient safety. Two new studies from Hospital for Special Surgery (HSS) researchers provide what the institution calls “important early evidence” in terms of perioperative considerations for these patients.
The studies, authored by HSS anesthesiologist Oliver PF Panzer, MD, and presented at last-week’s American Society of Regional Anesthesia and Pain Medicine (ASRA) Regional Anesthesiology and Acute Pain Medicine Meeting in Phoenix, “highlight the need for clear, evidence-based guidance as the use of GLP-1s expands,” stated the institution.
“The effect of these drugs in patients undergoing surgery raises concerns for anesthesiologists,” stated Dr. Panzer. “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.”
The first study, “Cross Sectional Assessment of Preoperative Gastric Content with Ultrasound in Patients Taking GLP-1 Agonists,” explores how GLP-1s affect gastric emptying in patients scheduled for surgery.
“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,” stated 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. 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.”
During the multicenter, prospective, cross-sectional observational study, anesthesiologists used ultrasound in pre-op holding areas 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 studied over roughly 17 months. Clear fluid >1.5ml/kg or solid content indicated a full stomach. Adherence to American Society of Anesthesiology NPO fasting guidance was required of each patient.
The researchers, according to HSS, found “no significant difference in the incidence of full stomach between patients taking GLP-1s and those who do not.” They did note that overall fasting times for solids tended to be longer in full patients in the GLP-1 group (23.73 hours) compared to the control group (16.63 hours), but said the results had no statistical significance.
Dr. Panzer stated that the results stand “in contrast to what most studies have shown so far. 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.”
Dr. Panzer said HSS hopes to follow up this study with research to determine if 24 hours of solid food fasting is helpful in reducing full stomach in patients on GLP-1s. He added that “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.”
A retrospective review study, “Institutional Trends in Glucagon-Like Peptide-1 Receptor Agonist Use Among Hip and Knee Arthroplasty Patients, 2021-2024,” explores the prevalence of GLP-1 agonist use among HSS patients undergoing primary and revision total hip arthroplasty and total knee arthroplasty.
Dr. Panzer and his colleagues found GLP-1 use among the 45,537 adult patients reviewed increased significantly over the four-year period of the study, rising from 3.69% of the patients in 2021 to 12.84% in 2024. Semaglutide and tirzepatide accounted for 88% of all GLP-1 use among these patients in 2024.
The researchers found higher rates of GLP-1 use among 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’re just at the beginning of this investigative journey, so there is a lot more insight to come,” stated Dr. Panzer.
