Is the level of cleanliness using segmental Boston bowel preparation scale associated with a higher adenoma detection rate?

Background: The impact of Boston bowel preparation scale (BBPS) scores on the adenoma detection rate (ADR) in each segment has not been adequately addressed. The aim of this study was to determine the association between segmental or overall ADR and serrated polyp detection rate (SDR) with segmental and total BBPS scores.

Methods: All outpatient screening colonoscopies with documented BBPS scores were retrospectively reviewed at a tertiary institution from January to December 2013. Chi-square tests and logistic regression were used to analyze the detection rates of adenomas and serrated polyps with bowel prep scores. Odds ratios were calculated using logistic regression that controlled for withdrawal time, age, body mass index, diabetes status and sex.

Results: We analyzed 1991 colonoscopies. The overall ADR was 37.5% (95% confidence interval [CI], 35.3-39.6). There was a significant difference in the overall ADR, and in SDR across all bowel category groups, with total BBPS scores of 8 and 9 having lower detection rates than scores of 5, 6 and 7. As the quality of bowel preparation increased, there was a statistical decrease in the ADR (odds ratio [OR] 0.79 [CI 0.66-0.94], P=0.04) of the right colon, while in the left colon, there was a statistical decrease in SDR (OR 0.78, [CI 0.65-0.92] P=0.019).

Conclusion: Segmental ADR and SDR both decreased as prep scores increased, decreasing notably in patients with excellent prep scores of 8 and 9. A possible explanation for this unexpected discrepancy may be related to longer and better visualization of the mucosa when cleansing and suctioning is necessary.