Clinical Study on the Application of Low-Dose 2L Lactulose Combined with Linaclotide in Bowel Preparation Before Colonoscopy

Aim This study aims to evaluate the efficacy and safety of low-dose 2L lactulose combined with linaclotide for bowel preparation prior to colonoscopy. Methods This was a single-blind, randomized controlled clinical study enrolling patients undergoing colonoscopy. All participants were randomly assigned in a 1:1:1 ratio to three groups: the 2L lactulose + linaclotide (L) group, the 2L lactulose group, and the 3L polyethylene glycol (PEG) group. The primary outcome was bowel cleansing quality evaluated using the Boston Bowel Preparation Scale (BBPS). Secondary outcomes included colonoscopy findings, palatability, tolerability, and acceptability, assessed via the Visual Analog Scale (VAS), sleep quality, and willingness to repeat the preparation. Safety was evaluated based on adverse events. Additionally, a subgroup analysis was conducted for patients with constipation. Results A total of 366 patients were included in the intention-to-treat (ITT) analysis. The adequate bowel preparation rates were significantly higher in the 2L lactulose + L group (90.1%; 95% confidence interval [CI], 83.5%-94.2%) and the 2L lactulose group (83.5%; 95% CI, 75.8%-89.0%) compared to the 3L PEG group (74.2%; 95% CI, 65.8%-81.1%; p = 0.004). The 2L lactulose + L group had significantly lower incidence of nausea (19.0% vs 32.3%, p = 0.018), vomiting (9.1% vs 18.5%, p = 0.032), and bloating (15.7% vs 35.5%, p < 0.001) compared to the 3L PEG group. There were no significant differences between the combined 2L lactulose + L group and the 2L lactulose group in terms of bowel preparation efficacy, palatability, tolerability, or willingness to repeat the regimen; however, both groups were superior to the 3L PEG group in these aspects. The 3L PEG group was more likely to cause sleep disturbances compared to the 2L lactulose group (p = 0.016). No significant differences were observed among the three groups in Boston Bowel Preparation Scale (BBPS) scores, polyp detection rate, adenoma detection rate, or cancer detection rate. In the subgroup analysis of patients with constipation, the three groups showed comparable efficacy; however, the 2L lactulose + L group had a higher BBPS score in the right colon compared to the 2L lactulose group (p = 0.014). Conclusion Low-dose 2L Lactulose combined with linaclotide regimen demonstrates superior potential than 3L PEG in terms of efficacy, safety, and patient experience, offering a more optimal alternative for bowel preparation.