24-hour Clear Liquid Diet vs. Standard Fasting for Upper Gastrointestinal Endoscopy in Patients Taking Agonists of the GLP-1 Receptor
Key facts
- Where
- Coimbra, PortugáliaSee the site
Where in Portugália
- Portuguese Oncology Institute of CoimbraCoimbra, PortugáliaNo longer taking part
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Trial details
- Who runs it
- Portuguese Oncology Institute, Coimbra
- Trial code
- NCT07929233
- Record updated
- 2026. november 10.
- Original description
GLP-1 receptor agonists delay gastric emptying and are associated with a higher rate of retained gastric content (RGC) during upper gastrointestinal endoscopy, even under standard fasting. No randomized trial has compared fasting strategies in this population. CLEAR-GLP1 is a multicentre, international, investigator-blinded randomized trial comparing a 24-hour clear liquid diet (followed by a 2-hour fast) with standard fasting (6 hours for solids, 2 hours for clear liquids) in adults on GLP-1 RA therapy undergoing elective upper endoscopy. GLP-1 RA therapy is not interrupted in either arm. The primary outcome is the rate of clinically significant RGC, defined as a GRACE stomach score of 0.Read full original descriptionShow less
24-hour Clear Liquid Diet vs. Standard Fasting for Upper Gastrointestinal Endoscopy in Patients Taking Agonists of the GLP-1 Receptor (CLEAR-GLP1 Trial): a Randomized, Parallel-group, Multicentre, International Clinical Trial
GLP-1 receptor agonists delay gastric emptying and are associated with a higher rate of retained gastric content (RGC) during upper gastrointestinal endoscopy, even under standard fasting. No randomized trial has compared fasting strategies in this population. CLEAR-GLP1 is a multicentre, international, investigator-blinded randomized trial comparing a 24-hour clear liquid diet (followed by a 2-hour fast) with standard fasting (6 hours for solids, 2 hours for clear liquids) in adults on GLP-1 RA therapy undergoing elective upper endoscopy. GLP-1 RA therapy is not interrupted in either arm. The primary outcome is the rate of clinically significant RGC, defined as a GRACE stomach score of 0.
Inclusion: Age ≥ 18 years; Current treatment with a GLP-1 receptor agonist for at least 4 weeks, regardless of indication; Referral for elective upper gastrointestinal endoscopy (isolated or combined with colonoscopy); Informed consent for both the upper gastrointestinal endoscopy procedure and study participation.
Exclusion: Previously diagnosed gastroparesis; Prior major gastric/esophageal surgery (e.g., gastrectomy, gastric bypass); Urgent/emergency endoscopy; Known or suspected upper gastrointestinal obstruction; Pregnancy; Refusal or inability to comply with the assigned fasting protocol.