Influence of the Timing of Colonoscopy on the Bowel Preparation Quality

Abstract

Introduction: Colonoscopy in an essential screening tool to decrease the risk of colorectal cancer. Physicians require a clear view of the colonic mucosa to detect polyps. Previous studies have suggested that a shorter interval between bowel preparation and the procedure leads to better bowel preparation. Aim: The aim of this study was to assess the influence of the timing of repeat colonoscopies on the bowel preparation quality. The primary outcome of this study was to determine the quality of bowel preparation in morning vs. afternoon colonoscopies. The secondary outcomes were to assess the adenoma detection rate (ADR) as well as the demographic differences between patients with adequate vs. inadequate prep. Methods: A retrospective study was conducted for all screening colonoscopies over the past three years using two-day split bowel preparation in adults with history of inadequate bowel preparation, yielding 651 colonoscopies. Preparation quality noted as “poor” or “unacceptable” was recorded as inadequate, while “fair”, “good,” or “excellent” was recorded as adequate. Colonoscopies performed prior to 12:00 PM were deemed “early” and those after 12:00 PM “late.” Demographic information including gender, race, body mass index was recorded, as were use of narcotics or promotility agents. The histology of each polyp and the endoscopist for all colonoscopies were recorded. The data was then broken down into: Early adequate, early inadequate, late adequate, and late inadequate. Chi-Square analysis was used. Demographic data and use of narcotic or promotility agents were broken down into percentages per group. ADR were calculated for each endoscopist using the colonoscopies with adequate preparation.Table 1: Demographic information and medication useFigure 1Results: Out of the 651 colonoscopies, 332 were repeats with 2-day prep. Of those, 224 were Early Adequate, 62 were Early Inadequate, 34 were Late Adequate, and 12 were Late Inadequate. There was no significant relationship between early colonoscopies and adequate prep, based on P value of Ch-Square = 0.5, and P value of Yates-corrected Chi-Square = 0.6. Conclusion: In chart review of screening colonoscopies in adults, early colonoscopy was not shown to be significantly superior than late colonoscopy after two-day prep. Both inadequate groups had a higher percentage of narcotic use than those in the adequate prep groups. ADR were calculated. This requires further study to establish guidelines.Figure 2