Risk factors for inadequate bowel preparation before colonoscopy: A retrospective cohort study.

Background: Bowel preparation is a critical step in colonoscopy and endoscopic surgery. Adequate and effective bowel cleansing significantly improves lesion detection rates while reducing operative risks and complications.

Aim: To investigate the current state of inadequate bowel preparation in patients undergoing colonoscopy, identify the contributing factors, and develop interventions.

Methods: This study was designed as a retrospective cohort study. A convenience sampling method was used to select 484 patients who underwent colonoscopy at Beijing Chao-Yang Hospital, Capital Medical University, from October 2023 to October 2024. General patient data, disease-related variables, and the Boston bowel preparation scale were collected. Logistic regression analysis was conducted to identify the factors associated with inadequate bowel preparation.

Results: Among the 484 patients, the rate of inadequate bowel preparation was 25.8% (125/484). Influential factors for poor bowel preparation included history of colorectal surgery [odds ratio (OR) = 5.814], low-residue diet 1 day prior (OR = 0.145), time interval from last dose to start of examination (OR = 1.447), total exercise time after medication (OR = 0.992), and total number of bowel movements after medication (OR = 0.900) (all P < 0.05).

Conclusion: This study highlights several modifiable and non-modifiable factors influencing bowel preparation, such as surgical history and behavioral adherence. The findings support implementing dietary adjustments, optimized laxative timing, physical activity guidance, and tailored strategies for high-risk patients to improve bowel cleansing and enhance the diagnostic accuracy of colonoscopy.