Residual gastric content after holding of glucagon-like peptide-1 receptor agonists before elective surgery: a cross-sectional study - The RESIDUAL study

Citation:

Boudreau C, Couture M, Rousseau-Saine N, Laferrière-Langlois P, Roy-Renaud É, Burey J, et al. Residual gastric content after holding of glucagon-like peptide-1 receptor agonists before elective surgery: a cross-sectional study - The RESIDUAL study. BMC Anesthesiol. 2026. doi:10.1186/s12871-026-03999-2

This episode asks whether fasted elective-surgery patients who held weekly injectable glucagon-like peptide-1 receptor agonists for at least 7 days still had more residual gastric content. Evidence is very uncertain whether use was associated with increased residual gastric content; aspiration outcomes were not collected.

Study at a glance

- Design and setting: Prospective cross-sectional study of fasted adults scheduled for elective surgery under anesthetic care at two university-affiliated hospitals in Montreal, Quebec, Canada, from October 2024 through February 2025; registered at ClinicalTrials.gov, NCT06500143.

- Population: 94 patients undergoing elective procedures were included; 1 patient in the GLP-1 RA group was excluded after gastric ultrasound because the last dose was less than 7 days before surgery. 93 patients were analyzed: 52 in the GLP-1 RA group and 41 controls. Female sex was 40.9%. Inclusion required age at least 18 years, American Society of Anesthesiologists physical status I to IV, and fasting according to Canadian guidelines. In the exposure group, 50/52 (96%) received semaglutide, one patient received tirzepatide, one patient received dulaglutide, 45/52 (87%) had diabetes as the treatment indication, and median time since last dose was 11 days (IQR 9 to 13).

- Exposure and comparator: Exposure was weekly injectable semaglutide, tirzepatide or dulaglutide use for more than 4 weeks, regardless of indication, with the last dose at least 7 days before surgery. The comparator group was not receiving any GLP-1 RA. Specific drug, dose in milligrams, and day of last injection were collected.

- Primary outcome: Increased residual gastric content on preoperative gastric ultrasound after guideline-concordant fasting was defined as thick liquid, solid content, or more than 1.5 mL/kg clear liquid. It is very uncertain whether GLP-1 RA use was associated with increased residual gastric content: 22/52 (42.3) in the GLP-1 RA group versus 10/41 (24.4) in controls; unadjusted prevalence ratio 1.73, 95% CI 0.96 to 3.75; adjusted prevalence ratio 1.65, 95% CI 0.7 to 3.7; adjusted average treatment effect 15.4%, 95% CI -10 to 35.6; p-value not reported (very low certainty).

- Key secondary outcome: Exploratory analyses were also very uncertain. For increased residual gastric content, the adjusted odds ratio per additional day since last GLP-1 RA injection was 1.08, 95% CI 0.86 to 1.39; per hour since last oral intake was 1.12, 95% CI 0.9 to 1.46; and per mg semaglutide dose was 2.19, 95% CI 0.47 to 12.7. p-values were not reported (very low certainty).

- Confounding: The primary adjusted analysis used propensity-score overlap weighting for age, sex, American Society of Anesthesiologists physical status classification, BMI, diabetes, opioid use, moderate to severe preoperative pain (> 3 on the verbal rating scale), and time since last oral intake; balance threshold was 0.1 with no variables imbalanced. The planned augmented inverse probability weighting estimator was changed because of inadequate covariate balancing. Sensitivity analysis with augmented inverse probability weighting showed prevalence ratio 1.84, 95% CI 0.74 to 4.24, and average treatment effect 18.1%, 95% CI -10.2 to 38.7. Residual confounding by unmeasured diabetes-related factors remained a serious concern.

- Risk of bias and certainty: ROBINS-I overall risk of bias was Serious, driven mainly by serious bias due to confounding. Selection of participants, exposure classification, deviations from intended exposure, and selection of reported result were Moderate; missing data and outcome measurement were Low. Overall GRADE certainty for increased residual gastric content was very low because of residual confounding, indirectness for clinical aspiration risk, and imprecision.