Good is better than excellent: bowel preparation quality and adenoma detection rates

Abstract

Background: Inadequate bowel cleansing is associated with missed lesions, yet whether polyp and adenoma detection rates (PDR, ADR) increase at the highest levels of bowel cleanliness is unknown.

Objective: To evaluate the association between bowel preparation quality by using the Boston Bowel Preparation Scale (BBPS) and PDR and ADR among colonoscopies with adequate preparation.

Design: Cross-sectional analysis.

Setting: Boston Medical Center (BMC) and the Clinical Outcomes Research Initiative (CORI).

Patients: Average-risk ambulatory patients attending screening colonoscopy with adequate bowel preparation defined as BBPS score ≥6.

Interventions: Colonoscopy.

Main outcome measurements: PDR and ADR stratified by BBPS score.

Results: Among the 3713 colonoscopies at BMC performed by 19 endoscopists, the PDR, ADR, and advanced ADR were 49.8%, 37.7%, and 6.0%, respectively. Among the 5532 colonoscopies in CORI performed by 85 endoscopists at 41 different sites, the PDR was 44.5%, and the PDR for polyps >9 mm (surrogate for advanced ADR) was 6.2%. The PDR associated with total BBPS scores of 6, 7, and 8 were higher than those associated with a BBPS score of 9 at BMC (BBPS 6, 51%; BBPS 7, 53%; BBPS 8, 52% vs BBPS 9, 46%; P = .002) and CORI (BBPS 6, 51%; BBPS 7, 48%; BBPS 8, 45% vs BBPS 9, 40%; P < .0001). This trend persisted after we adjusted for age, sex, and race and/or ethnicity and was observed for ADR and advanced ADR. PDR was higher among good compared with excellent preparations at BMC (odds ratio [OR] 1.3; 95% confidence interval [CI], 1.0-1.5) and CORI (OR 4.7; 95% CI, 3.1-7.1).

Limitations: Retrospective study.

Conclusion: The PDR and ADR decreased at the highest levels of bowel cleanliness. Endoscopists finding a pristine bowel preparation should avoid a sense of overconfidence for polyp detection during the inspection phase of screening colonoscopy and still perform a careful evaluation for polyps. Furthermore, endoscopists expending additional effort to maximize cleansing of the bowel should never sacrifice on their inspection technique or inspection time.