Quality of bowel cleansing for afternoon colonoscopy is influenced by time of administration

Afternoon colonoscopies have higher failure rates, due primarily to poor bowel cleansing. Hypothesizing that the time of administration influences the quality of bowel cleansing, we compared the quality of bowel cleansing for afternoon colonoscopies in patients completing the preparation on the same day vs. the day before colonoscopy.Data on afternoon colonoscopies performed between July 2008 and April 2009 were obtained from our endoscopy database. Bowel-preparation options were 4L polyethylene glycol (PEG) or 2L PEG plus four bisacodyl tablets. Patients could take the preparation on the same day as the procedure or the day prior, or consume half the day prior and half the same day. Bowel-cleansing quality was reported as excellent, good, fair-adequate, inadequate, or poor. Multivariate logistic regression analysis evaluated the association between quality of bowel cleansing and time of preparation administration.Bowel cleansing was reported as poor or inadequate in 7% of patients, adequate in 63%, and good or excellent in 30%. Afternoon colonoscopies using the same-day 4L PEG preparation were 3.14 times more likely to have fair-adequate cleansing and 7.03 times more likely to have good or excellent cleansing when compared with the other options.Same-day 4L PEG preparation for afternoon colonoscopy confers better-quality cleansing than prior-day preparation.