How to predict adequate bowel preparation before colonoscopy using conventional polyethylene glycol: prospective observational study based on survey.

ABSTRACT

BACKGROUND AND AIM: The present study investigated the conditions and predictive factors for adequate bowel preparation using 4-L polyethylene glycol (PEG) preparation in clinical practice. METHODS: We conducted a prospective-survey-based observational study. The survey consisted of 14 questions that assessed the preparation method (group 1 split method for morning colonoscopy; group 2 full-volume method for same-day afternoon colonoscopy; group 3 full-volume method for next-day morning colonoscopy), dinner type and timing the day before colonoscopy, elapsed time after PEG consumption, and stool character and defecation frequency immediately before colonoscopy. Preparation status was compared using the Boston bowel preparation scale (BBPS). RESULTS: Total of 465 surveys (391 for group 1, 55 for group 2, 19 for group 3) were conducted. Mean BBPS score was highest in group 1 and lowest in group 3 (P < 0.001). Fasting dinner before colonoscopy group showed a higher mean BBPS than the diet group; eating before 6 p.m. and a low-residue diet showed a higher mean BBPS (P < 0.05). Defecation frequency (>5 times) was related to adequate preparation in the left colon and elapsed time (<5 h) to that in the right colon (P < 0.05). Liquid stool without solid material immediately before colonoscopy was related to adequate preparation (P < 0.001). CONCLUSION: In bowel preparation with 4-L PEG, elapsed time after PEG consumption (<5 h), defecation frequency (>5 times) and liquid stool without solid material immediately before colonoscopy were predictive factors for adequate bowel preparation just before colonoscopy.