Individualized Non-pharmacological Intervention for Bowel Preparation

Effect of an Individualized Non-pharmacological Intervention Based on a Predictive Model for Inadequate Bowel Preparation on Bowel Preparation Quality: a Three-arm, Prospective, Randomized Controlled Study

Colonoscopy is essential for the early detection of colorectal cancer. However, inadequate bowel preparation remains a common challenge, associated with reduced adenoma detection rates, prolonged procedure time, and increased healthcare costs. Current individualized regimens rely largely on higher laxative dosages-an approach with limited clinical utility. Non-pharmacological interventions, including dietary modification, physical activity, and health education, are safe and tend to have better patient adherence. The effectiveness of health education depends largely on message framing. Guided by information-framing theory, we developed an individualized non-pharmacological regimen. This randomized controlled trial aims to evaluate the efficacy of this regimen in improving bowel preparation quality.

A total of 339 patients are enrolled and randomly assigned in a 1:1:1 ratio to the information-framing + individualized bowel preparation (BP) group, the individualized BP group, and the control group. All patients receive oral instructions on bowel preparation. On this basis, the control group receives a standard BP regimen and written educational materials; the individualized BP group is assessed using a risk prediction model for inadequate bowel preparation, with the results disclosed to the patients. Those with a risk score ≥3.25 receive an enhanced BP regimen, while those with a risk score <3.25 receive the standard BP regimen, and all patients in this group receive illustrated educational materials. In the information-framing + individualized BP group, educational materials are further tailored according to the information framework theory. Specifically, patients with a risk score ≥3.25 receive loss-framed materials emphasizing the harms of non-adherence, whereas those with a score <3.25 receive gain-framed materials highlighting the benefits of adherence. On the day of the colonoscopy, patients' willingness to undergo a repeat colonoscopy and the occurrence of adverse events are recorded in the waiting area. Patients also complete the Bowel Preparation Adherence Behavior Assessment Scale and the Treatment Self-Regulation Questionnaire. Bowel preparation quality is evaluated by endoscopists blinded to group allocation using the Boston Bowel Preparation Scale (BBPS), and polyp/adenoma detection rates are also recorded.

Inclusion Criteria:

• age ≥ 18 years;
• outpatient scheduled for colonoscopy using oral laxatives for bowel preparation;
• able to understand the study and provide written informed consent.

Exclusion Criteria:

• undergoing emergency colonoscopy;
• suspected intestinal obstruction, stricture, or perforation;
• severe cardiac, cerebral, hepatic, or renal disease;
• severe psychiatric disorder;
• impaired consciousness or communication difficulties;
• pregnancy or lactation;
• previous enrollment in this study.