Introduction
Bowel preparation quality is a key determinant of colonoscopy performance and a recognized quality indicator, yet its interaction with adjunct detection technologies remains incompletely understood. Computer-aided detection (CADe) and mucosal exposure devices (MED) improve adenoma detection rates (ADR), but most studies have been conducted under controlled conditions excluding poorly prepared examinations. Furthermore, whether detection continues to improve across the full Boston Bowel Preparation Scale (BBPS) spectrum or plateaus once adequacy is reached remains uncertain.
Aims & Methods
To evaluate the independent and combined effects of bowel preparation quality, CADe, and MED on colonoscopic detection outcomes in a large real-world cohort. This was a secondary analysis of a prospective observational study (2021–2025) at a tertiary academic center including patients ≥45 years undergoing elective colonoscopy. Outcomes were ADR, advanced ADR (AADR), sessile serrated lesion detection rate (SSLDR), and adenomas per colonoscopy (APC). Generalized linear models were fitted using piecewise BBPS (threshold 5) to allow different associations below and above this level. Models adjusted for withdrawal time, interactions between withdrawal time and BBPS, CADe use, MED use, age, sex, and indication.
Results
A total of 3,661 patients were included (mean age 65 years, 51.2% female). CADe was used in 38.4% and MED in 17.5% of procedures. In unadjusted analyses, ADR, AADR, and APC peaked at BBPS 5; SSLDR peaked at BBPS 7. In adjusted models, detection improved numerically with increasing BBPS from 0 to 5, although estimates were imprecise. Above BBPS 5, no further improvement was observed: AADR and APC declined significantly with increasing BBPS in this range (OR 0.63, 95% CI 0.19–0.89; RR 0.66, 0.46–0.93), while ADR and SSLDR showed no statistically significant change.
Both CADe and MED were independently associated with higher detection across all BBPS levels, with parallel effects suggesting no interaction with preparation quality. For example, at BBPS 5, ADR was 38.4% with CADe vs 28.6% without, and 38.7% with MED vs 28.6% without. Similar improvements were observed for AADR and APC. MED was associated with a marked increase in SSLDR (OR 1.97, 1.38–2.81), nearly doubling detection, whereas CADe did not significantly improve SSLDR (OR 1.21, 0.87–1.67). Across models, adjunct use did not compensate for poor preparation, and detection remained lower at the lowest BBPS scores.
Conclusion
Colonoscopic detection demonstrates a nonlinear relationship with bowel preparation quality, improving up to a threshold (BBPS 5) and plateauing or declining thereafter. These findings suggest that achieving adequate preparation, rather than excellence, is the key quality target. CADe and MED provide consistent, independent improvements in detection across all levels of bowel preparation without evidence of interaction, supporting their routine use in clinical practice. However, importantly, their use does not compensate for inadequate preparation. Guidelines recommend prompt repeat of colonoscopy if preparation adequacy is not achieved.
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