Effectiveness of low-volume split-dose versus same-day morning polyethylene glycol regimen for adequacy of bowel preparation in patients undergoing colonoscopy: A single-blinded randomized controlled trial

Background Successful completion of colonoscopy depends largely on the quality of bowel preparation. Polyethylene glycol (PEG) is a commonly used preparation for colonoscopy. The timing of bowel preparation has evolved from previous day evening to the currently recommended split-dose regimen. It was observed that consumption of entire or a portion of PEG on the previous day can interfere with work and sleep. Hence, we designed this single-blinded randomized controlled trial (RCT) to evaluate the efficacy, tolerability, and acceptability of the same-day PEG as compared with lowvolume split-dose PEG in patients undergoing late morning colonoscopy. Methods A total of 384 patients were randomized to same-day (SD group; n = 192) and split-dose (SPL group; n = 192) bowel preparation. The patients in both the groups received bisacodyl 10 mg at bedtime on the day prior to colonoscopy. The patients in the SD group took 2 L of PEG between 5:00 AM and 7:00 AM on the day of colonoscopy. The SPL group took 1 L of PEG between 6:00 PM and 7:00 PM on the preceding day and another liter between 6:00 AM and 7:00 AM on the day of colonoscopy. The adequacy of bowel preparation was assessed using the Boston Bowel Preparation Scale (BBPS). Tolerability was scored by recording symptoms such as nausea, vomiting, bloating, and abdominal pain. Acceptability was based on the overall satisfaction, willingness to repeat the same preparation, and interference with sleep on the preceding night. Results The median (interquartile range, [IQR]) BBPS in the SD group was 8 (6-9) while that in the SPL group was 6 (5-8) and this difference was statistically significant (p < 0.001). Similarly, a significantly higher proportion of patients in the SD group (86%) achieved adequate bowel preparation (BBPS score >= 6) when compared to those in the SPL group (73.4%) (p = 0.002). Tolerability as assessed by nausea, vomiting, bloating, and abdominal pain was similar in both the groups. There was also no significant difference with respect to overall satisfaction of taking bowel preparation (p = 0.33) or willingness to repeat the same regimen (p = 0.37) between the two groups. Patients in the SPL group had more interference with sleep on the preceding night (54% vs. 14.5%, p < 0.001). Conclusion Same-day morning PEG regimen can be considered an effective, well-tolerated, and acceptable bowel preparation for colonoscopy.