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

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.