Effect of 3-Day Linaclotide Administration to Reduce the Polyethylene Glycol Volume for Colonoscopy Bowel Preparation: A Multicenter, Noninferiority, Randomized Controlled Trial

INTRODUCTION: Several studies have investigated the role of linaclotide in bowel preparation; however, dosage and timing still warrant further exploration. METHODS: This noninferiority randomized controlled study was performed in 16 medical centers. The eligible subjects were randomly assigned to 3 groups: the Lct + 3 L polyethylene glycol (PEG) group (group A), the 3 L PEG group (group B), or the Lct + 2 L PEG group (group C). The primary outcome was the adequate bowel preparation rate based on the Boston Bowel Preparation Scale. Safety was assessed based on the incidence of adverse reactions. RESULTS: A total of 1,607 eligible subjects were enrolled, and 1,545 colonoscopy videos were uploaded. In the intention-to-treat analysis, the results of the noninferiority test indicated that the adequate bowel preparation rate in group C (87.58%, 95% confidence interval [CI] 85.08%-90.62%) was neither inferior to that of group A (88.79%, 95% CI 86.11%-91.46%) nor group B (83.99%, 95% CI 80.88%-87.09%). The overall incidence of adverse reactions in group A was higher than that in group C (13.64% vs 8.19%, P = 0.012). There were no significant differences in polyp detection rate ( P = 0.089), adenoma detection rate ( P = 0.776), and bowel preparation completion rate ( P = 0.052). DISCUSSION: The adequate bowel preparation rate of the combination of 3-day linaclotide and 2 L PEG was neither inferior to the combination of 3-day linaclotide and 3 L PEG nor 3 L PEG alone in the average-risk population.