Comparison Between an Oral Sulfate Solution and a 2 L of Polyethylene Glycol/Ascorbic Acid as a Split Dose Bowel Preparation for Colonoscopy

Background/Aims: This study aimed to compare the efficacy and tolerability of an oral sulfate solution (OSS) versus 2 L of polyethylene glycol/ascorbic acid (2L-PEG/Asc) for bowel cleansing before colonoscopy. Methods: A prospective, single-center, single-blinded, noninferiority, randomized, controlled trial was performed. The primary outcome was the rate of successful bowel cleansing, evaluated using the Boston Bowel Preparation Scale (BBPS). Secondary outcomes were examination time, polyp, and adenoma detection rate (PDR and ADR), tolerability, and safety. Ease of use, palatability, intention to reuse, and satisfaction were evaluated using a questionnaire. Results: A total of 187 participants were randomized to receive either OSS (n=93) or 2L-PEG/Asc (n=94). Successful bowel cleansing was achieved in 86.0% (80/93) of the OSS group, which was noninferior to the 2L-PEG/Asc group (88.3%, 83/94), with a difference of -2.3% by ITT analysis [95% confidence interval (CI) -12.0 to +7.4]. The withdrawal time of the OSS group was significantly shorter than that of the 2L-PEG/Asc group (11.8 +/- 5.2 vs. 14.3 +/- 8.5; P=0.016). Ease of use, palatability, intention to reuse, and satisfaction were similar between the 2 groups. Adverse events were also similar between the 2 groups. Mucosal erythema (4.3%) and aphthous lesions (2.1%) were found only in the 2L-PEG/Asc group. Conclusions: OSS was as effective as 2L-PEG/Asc for successful bowel cleansing and had acceptable tolerability. OSS is a promising and safe low-volume preparation alternative for colonoscopy. (Clinical trial registration number: NCT02761213.)