Effect of the Weekend on Bowel Preparation Quality in Outpatient Colonoscopies

Inadequate bowel preparation has been associated with a higher likelihood of missing adenomatous polyps. Colonoscopies immediately following a weekend may be prone to inadequate bowel preparation. This study aims to evaluate if day of the week is a predictor of bowel preparation adequacy, while assessing other patient and procedural variables and their effect on the Boston Bowel Preparation Scale (BBPS).

A retrospective review was conducted of all adult patients undergoing outpatient colonoscopy between January 2015 and April 2020. Adequacy of bowel preparation was compared among all days of the week and days following federal holidays. Secondary outcomes included patient demographics, indication and timing of the procedure.

Of 4,279 colonoscopies, Monday had the highest rate of inadequate preparation (BBPS < 6) (16.5%) compared to other days of the week (p < .001). Post-holiday procedures were not associated with poor bowel preparation (p = .901). Similarly, on multivariate analysis, we found that procedures on Monday (OR 1.67 95%CI 1.33-2.10, p < .001) and African-American race (OR 1.34 95%CI 1.11-1.62, p = .003) were associated with inadequate bowel preparation. Females were more likely to have adequate bowel preparation (OR 0.71 95%CI 0.59-0.86, p < .001).

Bowel preparation on Mondays is more likely to be inadequate than other days of the week. Additionally, gender and ethnicity appear to be associated with quality of bowel preparation. A better characterization of procedural and patient variables can lead to a more personalized approach to bowel preparation.