Comparison of Objectively Assessed Versus Patient-Reported Clarity of Last Rectal Effluent for the Prediction of Quality of Bowel Preparation for Colonoscopy: A Prospective, Case-Control Study.

Introduction: Colonoscopy is a crucial procedure for various clinical purposes, including screening for colorectal cancer. Adequate bowel preparation is essential for its success. Poor bowel preparation can lead to bad outcomes. An objective assessment of bowel preparation quality is typically only possible after the colonoscope is inserted. This study aimed to objectively correlate the clarity of last rectal effluent, directly collected in a transparent container, with the quality of bowel preparation, and compare it with patient-reported descriptions.

Methods: This prospective, single-centre, case-control study obtained ethical clearance and included patients aged >18 years undergoing colonoscopies. Cases included patients who collected the last rectal effluent and took photographs, while controls relied on verbal descriptions. Data collected included demographics, clinical information, bowel preparation quality, and lastly, stool clarity. A statistical analysis was performed to identify correlations and associations.

Results: Of the 70 included patients, 45 were male. The mean age was 35.8 ± 14.3 years. Cases had a higher mean age (37.8 ± 14.6). A higher number of cases had comorbidities (11, 68.8%). Photographic recording of the last rectal effluent was not associated with the adequacy of bowel preparation. Thin yellow fluid was the most common last-rectal effluent clarity (33, 47.1%). Thin, clear fluid was significantly associated with adequate bowel preparation.

Conclusion: Objective assessment of last rectal effluent clarity correlates with the quality of bowel preparation. This can improve the quality of bowel preparation for colonoscopies and potentially reduce the need for repeat procedures, contributing to better patient outcomes and cost savings in healthcare systems.