Introduction
Inadequate bowel preparation is linked to reduced adenoma detection rates (ADR), and establishing a threshold for bowel preparation below which colonoscopies should be repeated early is crucial for patient outcomes. However, manual bowel cleansing efficacy evaluation relies on the clinical observer's experience, resulting in subjectivity with clinical and economic implications. The Boston Bowel Preparation Scale (BBPS) is the most validated scoring scale. Our group previously constructed an AI-based bowel preparation assessment model to calculate e-BBPS scores.
Aims & Methods
This prospective, single-center study was conducted at the Eighth Affiliated Hospital, Sun Yat-sen University in China from October 2021 to November 2022. Eligible patients underwent screening colonoscopy by one of three study endoscopists. The AI calculated the e-BBPS score during colonoscope withdrawal. The endoscopist assessed bowel preparation adequacy using BBPS after the colonoscopy. If both BBPS and e-BBPS deemed bowel preparation adequate, the same endoscopist performed a second colonoscopy. If either considered it inadequate, the patient underwent bowel re-cleansing before the second colonoscopy. Video recordings were evaluated for bowel preparation using BBPS by five independent endoscopist raters.
Results
From October 8, 2021, to November 9, 2022, a total of 393 patients were included for analysis. In patients with unqualified-AI, the >5mm AMR was significantly higher than in patients with qualified-AI (p=0.0056, OR 0.2734, 95% CI 0.1139, 0.6565), as were the AMR <0.001 (p=0.2532, 95% CI 0.1583, 0.4052), diminutive AMR (p<0.001, OR 0.2160, 95% CI 0.1206, 0.3867), >5mm PMR (p=0.0152, OR 0.4335, 95% CI 0.2288, 0.8213), and PMR (p <0.001, OR 0.4532, 95% CI 0.3447, 0.5958). No significant differences were observed in the overall >5mm ADR, ADR, >5mm PDR, and PDR. In the first pass, no statistical differences were found in ADR between the qualified-AI and unqualified-AI groups, though there was a trend toward a higher ADR in the qualified-AI group. In the second pass, patients in the qualified-AI group achieved significantly lower >5mm ADR, ADR, diminutive ADR, advanced ADR, >5mm PDR, and PDR compared to those in the unqualified-AI group.
Cohen's kappa analysis revealed high agreement between expert raters, clinical scoring, and e-BBPS (ranging from 0.7791 to 0.8322). However, the agreement between general endoscopists and other raters was only low to moderate (0.2937 to 0.6071). Fleiss' kappa also indicated that the overall agreement among all raters was only 0.575 (p < 0.001, 95% CI 0.574, 0.575), while the Fleiss' kappa for Expert and Clinical scoring, as well as Expert, Clinical scoring, and e-BBPS were 0.809 (p < 0.001, 95% CI 0.807, 0.810) and 0.800 (p < 0.001, 95% CI 0.799, 0.801), respectively.
Conclusion
This study validates the e-BBPS bowel preparation evaluation threshold, confirming that patients with a score of ≤3 have adequate bowel preparation for detecting >5mm adenomatous polyps, while those with a score of >3 require repeat bowel preparation. This conclusion supports the implementation and promotion of fully automated bowel preparation assessment systems, which may improve the objectivity of bowel preparation evaluation and standardize clinical practice for screening colonoscopies in the future.
