Comparison of Bowel Cleansing Efficacy Between Same-day Dose Versus Split Dose

Split dose bowel cleansing is recommended method for colonoscopy. For afternoon colonoscopy, same-day dose of bowel cleansing is alternative option. Recently, same-day bowel cleansing for morning colonoscopy was validated. To date, there was no study which compared the bowel cleansing efficacy between same-day dose and split dose regardless of colonoscopy time. The aim of current study is to compare the bowel cleansing efficacy, adverse events, and patient's tolerability between the two group. Subjects who underwent colonoscopy for various reasons were included. After agreeing to participate in the study, study participants were randomly assigned to split dose or same day dose group. Bowel cleansing is done using polyethylene glycol (PEG). All colonoscopy was done between 10 AM to 6 PM. Study participants were instructed to ingest 500ml PEG every 15 minutes. Subjects who were assigned to split dose group ingested 2L PEG from 9PM 1 day before colonoscopy. Remaining 2L PEG was ingested 3-5 hours before colonoscopy. In the same-day dose group, bowel cleansing was started from 5AM for subjects who were scheduled to receive colonoscopy in the morning. Afternoon colonoscopy group in the same-day dose group ingested 2L PEG from 5AM. Remaining 2L PEG was finished 3-5 hours before colonoscopy. Bowel cleansing efficacy was assessed using Boston bowel preparation scale. Vital signs and laboratory tests were checked before colonoscopy. Study participants completed questionnaire which contained patient's satisfaction, tolerability, and adverse event during bowel cleansing. Bowel cleansing efficacy, patient's tolerability, and safety profile were compared between the two groups. Successful bowel cleansing was estimated 85% for split dose group. The investigators set 10% for inferior margin. Considering 10% drop out, a total of 352 subjects will be recruited.