INTRODUCTION: Glucagon-like peptide-1 receptor (GLP-1R) agonists have been increasingly prescribed for weight loss and glycemic control. The potential side effect of slowed gastric emptying may increase risk of regurgitation and aspiration. Our primary aim was to investigate the incidence of retained gastric contents (RGCs) among appropriately fasted patients taking a GLP-1R agonist compared to those not taking a GLP-1R agonist presenting for upper gastrointestinal endoscopy (UE). METHODS: A retrospective chart review of patients undergoing UE was conducted. For the GLP-1R group, included were patients aged 18 years or older who had documentation of taking a GLP-1R agonist within 30 days prior to the procedure, adhered to standard fasting guidelines, and had clear documentation in the electronic medical record of gastric findings during endoscopy. This group was compared to a group of agematched controls. The primary outcome was the incidence of RGCs. Secondary outcome included a propensity-weighted analysis of the odds ratio of taking a GLP-1R and having RGCs. RESULTS: Included were 940 patients who presented for UE between July 2022 and December 2023 (470 GLP-1R and 470 controls). RGCs were found in 59/470 (12.6 %) of GLP-1R patients compared to 26/470 (5.5 %) of controls (P <
0.001). Propensity-weighted analysis found a significant association between the use of GLP-1R and retained gastric contents [OR = 1.92, 95 % CI (1.04, 3.53)]. CONCLUSIONS: A higher incidence of RGCs was found in appropriately fasted patients on a GLP-1R agonist who presented for UE. After controlling for the differences between the two study groups, RGC's were correlated to GLP-1R agonist use. Anesthesiologists should remain vigilant regarding a potential increased risk of RGCs in appropriately fasted patients taking a GLP-1R agonist who present for surgery.