A randomized controlled trial evaluating a new 2-L PEG solution plus ascorbic acid vs 4-L PEG for bowel cleansing prior to colonoscopy.

Background: Bowel preparation is critical for the efficacy and safety of colonoscopy. Poor patient tolerance to bowel preparation has been associated with the high amount of fluid administered. A 2-L polyethylene glycol (PEG) solution containing ascorbic acid has been recently developed.

Aims: To compare the efficacy, safety and acceptability of 2-L PEG+ascorbic acid vs 4-L PEG for colonoscopy.

Methods: We designed a single blind randomized non-inferiority study in order to compare the two bowel preparations. A blinded assessment of cleansing was made by the endoscopist according to the Aronchick scale. Acceptability was assessed by questionnaire. Intention-to-treat (ITT) and per-protocol (PP) analysis were reported.

Results: Overall, 169 patients (PP: 166) were selected for the 2-L PEG+ascorbic acid and 170 (PP: 166) for the 4-L PEG. When rating global bowel cleansing at ITT, an excellent-good level was reported in 84.6% (PP: 86.2%) of patients who received 2-L PEG+ascorbic acid and 75.3% (PP: 77%) of patients who received 4-L PEG (p=0.04). Acceptability rate favoured 2-L PEG+ascorbic acid vs 4-L PEG (83% vs 76%; p=0.02).

Conclusions: 2-L PEG+ascorbic acid, completed with an additional L of clear fluids, provided bowel cleansing which appeared to be more effective and acceptable than 4-L PEG.