One-day versus three-day low-residue diet bowel preparation regimens before colonoscopy: a meta-analysis of randomized controlled trials.

The present study demonstrated that a 1-day LRD was as effective as a 3-day CLD in the quality of bowel preparation before colonoscopy and significantly improved tolerability of patients. In addition, constipation is an independent risk factor of poor bowel preparation, and the duration of LRD in patients with constipation still needs further clinical trials.