Purpose: Inadequate bowel preparation (IBP) is commonly observed during surveillance colonoscopy after colorectal resection. We investigated potential risk factors affecting bowel preparation.
Methods: We studied potential factors affecting bowel preparation quality. The Boston bowel preparation score was used to measure bowel preparation quality. Factors affecting IBP were analyzed, including age, body mass index, time elapsed between surgery and colonoscopy, and amount of bowel preparation drug consumed (conventional-volume vs. low-volume). Odds ratios were calculated for IBP.
Results: This retrospective cohort study included 1,317 patients who underwent colorectal resection due to malignancy. Of these patients, 79% had adequate bowel preparation and 21% had IBP. In multivariate regression analysis, a surveillance colonoscopy within 1 year after surgery and age >80 were used as independent predictors of IBP. IBP rate of the low-volume group was significantly higher than that of the conventional-volume group among patients who underwent a surveillance colonoscopy within 1 year after surgery.
Conclusion: For surveillance colonoscopy after colorectal resection, bowel preparation is affected by factors including colonoscopy timing after surgery and age. We recommend the use of conventional-volume 4-L polyethylene glycol solution when performing a surveillance colonoscopy, especially up to 1 year after surgery.
Keywords: Colonic neoplasms; Colonoscopy; Rectal neoplasms.