Oral Sulfate Solution Is as Effective as Polyethylene Glycol with Ascorbic Acid in a Split Method for Bowel Preparation in Patients with Inactive Ulcerative Colitis: A Randomized, Multicenter, and Single-Blind Clinical Trial

Background/Aims: Low-volume preparations for colonoscopy are gaining attention for their higher acceptability. However, the efficacy and safety of oral sulfate solution (OSS) preparations in patients with ulcerative colitis (UC) has not been well known. Therefore, we aimed to compare OSS and 2-L polyethylene glycol with ascorbic acid (PEG+Asc) for bowel preparation in inactive UC. Methods: A multicenter, randomized, single-blind study was conducted at six tertiary referral hospitals in Korea. Outpatients with UC who had stable disease activity were randomly allocated to the OSS group or the 2-L PEG+Asc group for bowel preparation before colonoscopy. The study outcomes included treatment efficacy, safety, tolerability, and acceptability. Bowel cleansing was assessed using the Boston Bowel Preparation Scale and rated as successful cleansing if the score was ≥6. Patient acceptance and tolerability were assessed using a 4-point ordinal scale. Additionally, disease activity and laboratory data before and after colonoscopy were evaluated to check for safety. Results: The OSS and 2-L PEG+Asc groups included 92 and 93 participants, respectively. No significant between-group difference was noted in successful cleansing (OSS [96.7%] vs 2-L PEG+Asc [97.8%], p=0.64). Moreover, the safety, acceptance, and tolerability were not significantly different (all p>0.05). Furthermore, no significant changes were found in serum electrolytes or disease activity in either group. Conclusions: OSS is effective for colonoscopy cleansing, has acceptable tolerability, and does not affect disease activity; thus, it can be used safely for bowel preparation in patients with inactive UC.