A prospective, single-blinded, non-inferiority, randomized controlled study comparing the effectiveness and safety of oral lactulose combined with carbohydrate-containing clear liquids versus 3-L polyethylene glycol electrolyte for colonoscopy bowel preparation.

Background: Polyethylene glycol electrolyte solution (PEG-ELS) is the standard for bowel preparation but often suffers from poor patient compliance and tolerability due to its high-volume requirement. This prospective, single-blinded, non-inferiority, randomized control trial aims to investigate the efficacy and safety of a lactulose-based regimen as an alternative for bowel preparation.

Methods: Two hundred nine patients were randomly allocated to receive either a combination regimen consisting of 133.4 g lactulose in 200 mL, 800 mL carbohydrate-containing clear liquid, 2L additional water, and 5 g simethicone (n = 104) or 3L PEG-ELS with 5 g simethicone (n = 105), both administered in a split-dose format. The primary outcome was the rate of adequate bowel preparation, measured by the Boston bowel preparation score (BBPS). Adequate bowel preparation was defined as a BBPS score of 2 or 3 in all colon segments. Secondary outcomes included the percentage of high-quality bowel preparation (defining as a total BBPS score of 8 or 9), polyp detection rate (defining as the percentage of procedures where at least one polyp was detected), willingness to repeat the bowel preparation, adverse events, and changes in blood glucose and electrolyte levels.

Results: The rate of adequate bowel preparation (96.2% vs. 97.1%, p = 0.691), the percentage of high-quality preparation (62.5% vs. 66.7%, p = 0.529), average total BBPS scores (p = 0.607), polyp detection rates (66.3% vs. 77.1%, p = 0.083), and tolerability and acceptability outcomes, including satisfaction (p = 0.729) and willingness to repeat preparation (p = 0.744), were not statistically different between the two arms. Adverse events and changes in blood glucose and electrolytes showed no significant differences (all p > 0.05).

Conclusion: The combination of oral lactulose and carbohydrate-containing clear fluids was non-inferior to 3L PEG-ELS for bowel preparation adequacy and polyp detection, without statistically significant differences in terms of tolerability and safety.