July 22, 2025
Adequate bowel preparation is essential to facilitate examination of the mucosal surface and detect adenomas during colonoscopy. Prior research and clinical experience have demonstrated that multiple factors can impact bowel preparation quality. The rapidly rising use of glucagon-like peptide-1 (GLP-1) receptor agonists has caused gastroenterologists to question whether these medications can affect bowel preparation. To explore this issue, Mayo Clinic researchers reviewed the electronic health records of more than 6,000 adult patients undergoing colonoscopy, and they compared the quality of bowel preparation between a group of patients using GLP-1 receptor agonists and a control group. The results of the study were published in Gastrointestinal Endoscopy in 2025 and shared in a poster presented at Digestive Disease Week 2025.
"There is an exponential increase in the use of GLP-1 receptor agonists because of their potent impacts on management of diabetes, heart disease and reduction in body weight," explains Nayantara Coelho-Prabhu, M.B.B.S., a gastroenterologist and researcher at Mayo Clinic in Rochester, Minnesota, who served as the publication's corresponding author.
"These medications are known to delay gastrointestinal motility, which can adversely affect bowel preparation quality for colonoscopy," says Dr. Coelho-Prabhu. "Inadequate bowel preparation can significantly reduce the diagnostic accuracy and therapeutic safety of colonoscopy, potentially leading to missed lesions and the need for repeat procedures. This is clinically significant because poor bowel preparation is associated with increased procedural time, higher costs and greater patient discomfort due to the need for repeat colonoscopies."
Methods
The retrospective study included 3,344 patients using GLP-1 receptor agonists and 2,891 age- and sex-matched controls, all of whom underwent colonoscopy in 22 endoscopy units across 18 sites at Mayo Clinic sites in Minnesota, Wisconsin, Florida and Arizona. The researchers collected data on relevant patient comorbidities, type of bowel preparation, concurrent medications, quality of bowel preparation and findings on colonoscopy.
The researchers' primary endpoint was to assess the mean total Boston Bowel Preparation Scale (BBPS) for both study groups. Their secondary objectives included determining BBPS segment scores, rates of inadequate colonoscopy and adenoma detection rates (ADR) for both groups.
Results and conclusions
"Our study found that patients using GLP-1 receptor agonists are more likely to have inadequate bowel preparation during colonoscopy, even when we account for other comorbidities, such as diabetes, heart failure, inflammatory bowel disease, constipation and use of opioid medications," explains Dr. Coelho-Prabhu.
"Our study found that patients using GLP-1 receptor agonists are more likely to have inadequate bowel preparation during colonoscopy, even when we account for other comorbidities, such as diabetes, heart failure, inflammatory bowel disease, constipation and use of opioid medications."
Noteworthy study findings include the following:
- Baseline variables associated with suboptimal bowel preparation included the procedure setting (inpatient); sex (male); body mass index (higher); presence of type 2 diabetes mellitus, inflammatory bowel disease, heart failure and cirrhosis; and use of opioid medications.
- The total BBPS was significantly higher in control patients than in patients using GLP-1 receptor agonists (6.4 ± 1.6 versus 6.1 ± 1.7, P < 0.01), even after controlling for the above-mentioned variables.
- No significant difference in bowel preparation was detected between different classes of GLP-1 receptor agonists.
Next steps
Dr. Coelho-Prabhu explains that additional research is needed to clarify recommendations related to the use of GLP-1 receptor agonists before colonoscopy and whether any additional or modified preparation instructions could improve bowel preparation among patients using these medications. "Future studies should examine the optimal interval prior to colonoscopy when these medications should be held," says Dr. Coelho-Prabhu. "Alternatively, it would be helpful to know whether dietary changes such as full liquid diet prior to colonoscopy might be adequate to improve preps. These various measures need to be further studied."
For more information
Gala K, et al. Quality of bowel preparation for colonoscopy in patients on glucagon-like peptide-1 receptor agonists. Gastrointestinal Endoscopy. 2025;101:1068.f
Tome J, et al. Impact of glucagon-like peptide-1 receptor agonists on bowel preparation for colonoscopy. Presentation at: Digestive Disease Week 2025; San Diego.
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