A potential negative effect of glucagon-like peptide 1 (GPL-1) receptor agonists on bowel cleanliness in colonoscopy has been reported in literature. However, most of the evidence comes from retrospective studies.

The main aim of this study is to prospectively compare bowel preparation quality and overall tolerability of bowel preparation among diabetic patients treated with GLP-1 receptor agonists and not. Secondary outcomes included comparison of the number of polyps detected, cecal intubation rate, procedure duration and procedure-related complications among the two groups.

This prospective observational study has been conducted across 6 Italian Gastroenterology and Digestive Endoscopy units, which consecutively enrolled diabetic patients undergoing colonoscopy for any indication, both those treated with GLP-1 receptor agonists and those not. All patients received a low-volume, split-dose bowel preparation regimen. The Boston Bowel Preparation Scale (BBPS) was used to assess bowel cleansing quality, and the validated Lawrence score was employed to evaluate preparation tolerability in the two groups. Preliminary results are presented.

A total of 111 diabetic patients were enrolled, 36 (32.4%) in the GLP-1 group and 75 (67.6%) in the non–GLP-1 group. Two groups were comparable for age (70.6 ± 8.5 vs 70.4 ± 6.7 years, p = 0.90), sex distribution (p = 0.94), smoking status (p = 0.12), and diabetes-related complications (p = 0.75), body mass index (BMI, 25.9 ± 3.7 kg/m² vs 27.0 ± 4.6 kg/m², p = 0.16), diabetes duration (12.6 ± 7.9 vs 11.1 ± 6.9 years, p = 0.34).

No significant difference in bowel cleansing was found among the two groups (BBPS≥6 in 83.3% of the GLP-1 group and 76.0% of the non–GLP-1 group, p = 0.53). Tolerability was also comparable between groups: 20 (26.7%) patients in the non–GLP-1 group and 12 (33.3%) in the GLP-1 group reported no difficulty; 34 (45.3%) and 11 (30.5%) reported mild difficulty; 19 (25.3%) and 13 (36.1%) reported moderate difficulty; 2 (2.7 %) and 0 reported severe difficulty, respectively (p = 0.30). Cecal intubation rates were likewise similar (GLP-1: 88.9% vs non–GLP-1: 86.7%, p = 0.98). No significant difference in polyp per colonoscopy and colonoscopy duration were found. No colonoscopy-related complications occurred in either group.

This preliminary results did not reveal any significant difference in bowel cleansing quality and tolerability of preparation among diabetic patients taking GLP-1 receptors agonists or not as well as other key colonoscopy quality indicators.

Initial data in our cohort suggest a lower impact of GPL-1 receptor agonist on bowel preparation compared with what is currently reported in the literature and that diabetes itself is the main cause of inadeguate bowel preparation