Efficacy and tolerability of 1 L polyethylene glycol plus ascorbic acid with senna versus 2 L polyethylene glycol plus ascorbic acid for colonoscopic bowel preparation: Prospective, randomized, investigator-blinded trial

ObjectivesLow-volume polyethylene glycol plus ascorbic acid (PEG-Asc) reduces the dosage of colonoscopic bowel preparation (BP) solution, but is still poorly tolerated. Adding laxatives to the BP solution reduces the volume of fluid required, without affecting quality. This study aimed to compare 1 L PEG-Asc plus 24 mg senna (1L-PEG/AS) and conventional 2 L PEG-Asc (2L-PEG/A) regimens on BP quality and patient tolerability. MethodsA single-center, randomized, investigator-blinded, noninferiority trial was performed between June and August 2022. Outpatients scheduled for colonoscopy were randomized (1:1) to the 1L-PEG/AS or 2L-PEG/A group. The Boston Bowel Preparation Scale (BBPS) was used to evaluate BP quality. Adverse events and tolerability were surveyed using questionnaires. ResultsOverall, 344 patients received 1L-PEG/AS or 2L-PEG/A regimens. The baseline characteristics and adverse events of the two groups were comparable. The 1L-PEG/AS group showed noninferior adequate BP rates compared with the 2L-PEG/A group (88% vs. 89%, P = 1.00); overall BBPS was 7.1 +/- 1.5 and 7.2 +/- 1.5, respectively (P = 0.39). Higher willingness to repeat the BP was observed in the 1L-PEG/AS group (85% vs. 62%, P < 0.01). ConclusionsThe 1L-PEG/AS regimen was comparable to the 2L-PEG/A regimen in terms of BP adequacy, requiring lower BP solution volumes, with better patient tolerance. Thus, it may be a suitable alternative to the conventional BP solution for colonoscopy.The Japan Registry of Clinical Trials (jRCT1051220043).