Effect of Fasting Recommendations Among Patients Using GLP-1 Receptor Agonists

Not Applicable

Recruiting

• Conditions: Residual Gastric Contents; Pulmonary Aspiration of Gastric Contents

• Registration Number: NCT06839248
• Lead Sponsor: St Vincent's Hospital Melbourne

Brief Summary

The aim of this randomised controlled trial is to determine the effect of a 24-hour clear liquid diet compared to standard fasting guidelines on the proportion of participants who present with increased residual gastric contents during their study visit. It also aims to determine the effect of a 24-hour clear liquid diet compared to standard fasting guidelines on:

* Solid content or thick fluids

* Patient-reported outcome measures (PROMs), including thirst, hunger, nausea, fatigue, and anxiety.

* Compliance measures, including adherence with the intervention, time since last oral intake of solid foods, and time since last oral intake of clear liquids.

We will enrol adults who are currently using any once-weekly glucagon-like peptide-1 receptor agonist (GLP-1RA) medication. Participants will be allocated in a 1:1 ratio to follow a 24-hour clear liquid diet or standard fasting guidelines prior to attending a study visit where participants will undergo a blinded gastric ultrasound assessment.

Detailed Description

GLP-1 RAs have had a transformative impact on the management of obesity, cardiovascular disease, and type 2 diabetes. Despite this, this class of medications pose a significant challenge in the perioperative setting, as GLP-1 RAs are known to increase patients' risk of presenting to surgery with residual gastric contents even when standard fasting guidance is adhered to. Such residual contents pose a risk for devastating complications if they are aspirated during surgery. In procedures such as upper endoscopy, where clear visualisation of the gastric tract is essential, the presence of residual contents in the stomach may result in procedures being aborted, leading to patients being exposed to additional risks associated with having to repeat the procedure. Despite the urgent need for clear guidance based on reliable evidence, healthcare professionals are currently practicing in an almost complete absence of evidence regarding the management of GLP-1 RAs in the perioperative period.

Our trial aims to address the uncertainty around pre-procedure management of patients using GLP-1 RAs by evaluating whether a 24-hour clear liquid diet can reduce the likelihood of increased residual gastric contents in patients using once-weekly GLP-1 RA medications, compared to the standard fasting guidelines currently recommended before elective procedures. Standard fasting guidelines, as defined by the ASA and ANZCA, recommend clear liquids up to 2 hours before anaesthesia, a light or low calorific meal up to 6 hours before anaesthesia, and fasting from fried foods, fatty foods, or meat for at least 8 hours prior to anaesthesia.The trial will also examine the effect of this more stringent fasting guidance on outcomes including thirst, hunger, nausea, fatigue, and anxiety, which impact both comfort and satisfaction among patients undergoing surgery.

Study Timeline

• Study First Submitted: 2025-02-11
• Study First Submitted QC: 2025-02-16
• Study First Posted: 2025-02-21
• Study Start: 2025-06-20
• Status Verified: 2025-08
• Last Update Submitted: 2025-08-18
• Last Update Posted: 2025-08-22
• Primary Completion: 2026-02-09
• Study Completion: 2026-02-09

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 154

Inclusion Criteria

• Age ≥18 years old at enrolment.
• Have regularly administered any type of once-weekly GLP-1 RA medication for a period of at least one month prior to randomisation.
• If allocated to follow standard fasting guidelines, willing to adhere to ASA and ANZCA preoperative fasting requirements. This requires participants to only consume clear liquids up to 2 hours, a light or low calorific meal up to 6 hours, and fasting from fried foods, fatty foods, or meat for at least 8 hours prior to the trial visit.
• If allocated to follow a 24-hour clear liquid diet, willing to adhere to nothing-by-mouth (NPO) for solids and last intake of clear liquids no less than 2 hours prior to the trial visit.
• Provide a signed and dated informed consent form for study participation in line with the requirements of the human research ethics committee (HREC) of the study site.

Exclusion Criteria

Participants meeting any of the following criteria, indicative of abnormal anatomy and not validated by gastric ultrasound, will be excluded from this trial:

• Has a recent history of gastrointestinal bleed within the previous 1 month from enrolment.
• Has a history of previous lower oesophageal or gastric surgery.
• Has a known abnormal upper gastrointestinal anatomy, including hiatus hernia or gastric tumours.

In addition, participants meeting any the of following criteria will be excluded from this trial:

• Participant reports having been previously diagnosed with a clinically significant gastric emptying abnormality such as gastroparesis.
• Participant reports concomitant use of insulin.
• Unable to assume the right lateral decubitus position required for gastric ultrasound assessment.
• Participant has difficulty fully understanding PICF or study materials due to a primary language other than English.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Residual gastric contents	Immediately following fasting intervention	Difference in proportion of participants who present with increased residual gastric contents, defined as \>1.5mL/kg of clear fluids, thick fluids or solids, as assessed by gastric ultrasound using the clinical algorithm by Perlas and colleagues.

Secondary Outcome Measures

Name	Time	Method
Solid content or thick fluids	Immediately following fasting intervention	Difference in proportion of participants who present with solid content or thick fluids, assessed by gastric ultrasound using the clinical algorithm by Perlas and colleagues.
Anxiety	Immediately following fasting intervention	Mean difference in anxiety, assessed using the Visual Analogue Scale for Anxiety (VAS-A). Participants rate their level of anxiety along a scale of 0-10cm, where 10cm represents "most anxious I can imagine, and the end closest to 0cm the represents "not at all anxious".
Time since last oral intake of solid foods	Immediately following fasting intervention	Mean difference in time since last oral intake of solid foods, assessed using a dedicated case report form.
Thirst	Immediately following fasting intervention	Mean difference in thirst, assessed using the thirst distress and thirst intensity Visual Analogue Scales.; Participants rate their level of thirst distress along a scale of 0-10cm, where 10cm represents "extreme distress" and the end closest to 0cm the represents "not distressed". Participants rate their level of thirst intensity along a scale of 0-10cm, where 10cm represents "intense thirst" and the end closest to 0cm the represents "not thirsty". The average of the thirst intensity and the thirst distress score is calculated.
Fatigue	Immediately following fasting intervention	Mean difference in fatigue, assessed using a Visual Analogue Scale.; Participants rate their level of fatigue along a scale of 0-10cm, where 10cm represents "extreme fatigue", and the end closest to 0cm the represents "not fatigued at all".
Adherence to intervention	Immediately following fasting intervention	Difference in proportion of participants who adhere to allocated intervention, assessed using a dedicated case report form.
Hunger	Immediately following fasting intervention	Mean difference in hunger, assessed using the Hunger and Satiety Visual Analogue Scale.; Participants rate their level of hunger along a scale of 0-10cm, where 10cm represents "I have never been more hungry, and the end closest to 0cm the represents "I am not hungry at all".
Nausea	Immediately following fasting intervention	Mean difference in nausea, assessed using a Visual Analogue Scale.; Participants rate their level of nausea along a scale of 0-10cm, where 10cm represents "worst imaginable nausea", and the end closest to 0cm the represents "no nausea".
Time since last oral intake of clear liquids	Immediately following fasting intervention	Mean difference in time since last oral intake of clear liquids, assessed using a dedicated case report form.

Trial Locations

Locations (2)

Melbourne Gastro Oesophageal Surgery (MGOS); 🇦🇺 Melbourne, Victoria, Australia

St Vincent's Hospital Melbourne; 🇦🇺 Melbourne, Victoria, Australia