S702 Clock Shifts and Colonoscopy: Evaluating the Effect of Time Changes on Bowel Preparation Adequacy

Introduction: Colorectal cancer (CRC) is the second leading cause of cancer-related mortality in the United States. Detection and removal of precancerous polyps through screening colonoscopy plays a vital role in reducing CRC-related morbidity and mortality. High-quality bowel preparation is essential for adequate visualization and complete polypectomy. Several factors influence preparation quality, including timing, patient adherence, and physiologic rhythms. Spring Daylight Saving Time (DST) transitions may disrupt circadian rhythms and sleep patterns, potentially impacting patient compliance. This study investigates whether DST and Standard Time (ST) shifts are associated with differences in bowel preparation adequacy. Methods: We conducted a retrospective chart review at a large academic medical center, evaluating patients who underwent colonoscopy within 5 days before and 5 days after both the spring (DST) transition and the fall standard time (ST) transition, across the years 2021 to 2023. Bowel preparation adequacy was classified as adequate or inadequate according to Boston Bowel Preparation Score (BBPS); scores <6 were deemed inadequate. Chi-square test was utilized to compare categorical variables. Univariable logistic regression was used to assess associations between time shifts and preparation quality. Results: A total of 1825 patients were included: 911 patients surrounding the spring DST shift and 914 around the fall ST shift. Colonoscopy within 5 days after the DST transition was associated with a higher rate of inadequate bowel preparation (12.14% vs 7.68%) and significantly increased odds of inadequate preparation (odds ratio [OR] 1.62; 95% CI, 1.04–2.52; P = 0.036). No statistically significant differences were observed for preparation adequacy around the ST transition in the fall (OR: 1.13; 95% CI: 0.746-1.711; P = 0.564). There were no statistically significant differences in demographic or clinical characteristics between groups before and after each transition. Conclusion: Disruptions to circadian rhythms following the DST transition appear to negatively impact bowel preparation quality, potentially due to reduced compliance or physiologic dysregulation. These findings suggest a need for increased attention to bowel preparation instructions and scheduling in the peri-DST period. Further studies are warranted to validate these findings and explore interventions to mitigate the impact of DST on bowel preparation and screening colonoscopy outcomes.