Comparison of Bowel Cleansing Efficacy, Safety, Bowel Movement Kinetics, and Patient Tolerability of Same-Day and Split-Dose Bowel Preparation Using 4 L of Polyethylene Glycol: A Prospective Randomized Study

BACKGROUND: Split-dose bowel preparation is recommended for morning colonoscopy, although a same-day dose regimen is an alternative for afternoon colonoscopy. Same-day preparation for morning colonoscopy has rarely been evaluated. OBJECTIVE: We compared the bowel cleansing efficacy, bowel movement kinetics, safety profile, and patient tolerability of split-dose and same-day preparation using 4-L polyethylene glycol. DESIGN: This was a prospective, randomized, assessor-blinded study. SETTINGS: This study was performed at a tertiary center in Korea. PATIENTS: Study subjects were randomly assigned to the same-day or split-dose groups. For the same-day dose group, 4 L of polyethylene glycol were ingested on the day of colonoscopy starting at 5:00 am for morning colonoscopy or 7:00 am for afternoon colonoscopy. In the split-dose group, 2 L of polyethylene glycol were ingested at 9:00 pm the day before colonoscopy, and the remaining 2 L from 7:00 am for morning colonoscopy or from 10:00 am for afternoon colonoscopy. Colonoscopy was performed from 10:00 am. MAIN OUTCOME MEASURES: The efficacy of bowel cleansing was evaluated using the Boston bowel preparation scale. The participants completed questionnaires asking about adverse events, bowel movement kinetics, and tolerability of the preparation before colonoscopy. RESULTS: A total of 339 subjects were included (same-day dose = 172; split dose = 167). One subject in each group did not undergo colonoscopy. The rate of successful cleansing did not differ between the groups (same-day dose = 98.8% vs split dose = 98.2%; p = 0.681). There were no instances of hemodynamic instability or aspiration in either group. Tolerability, including overall satisfaction and willingness to reuse, were comparable between the groups. LIMITATIONS: This was a single-center study. CONCLUSIONS: The bowel cleansing efficacy, safety profile, and tolerability of same-day dosing with polyethylene glycol were comparable with those of split dose. Therefore, same-day dosing with 4 L of polyethylene glycol is a feasible bowel preparation method. See Video Abstract at http://links.lww.com/DCR/B44.