Reporting of Adenoma Detection by Segment: A Proposed New Quality Metric for Colonoscopy

Background and Aims

The adenoma detection rate (ADR), is a key quality metric for colonoscopy, but it might fail to measure differences in adenoma detection in different parts of the colon. Because many post-colonoscopy cancers arise in the proximal colon, differences in the ADR of proximal vs distal adenomas could be clinically important. Our aim was to determine the feasibility of measuring ADR for both the proximal and distal colon and to understand differences based on age, sex, and race.

Methods

We queried a large claims database (Health Care Service Corporation) to screen colonoscopies from 2016-2018 to determine the location and pathology of detected polyps. We measured the ADR in both the proximal (P-ADR) and distal (D-ADR) colon to determine differences in the ratio of P-ADR vs D-ADR by age, sex, and race.

Results

The cohort included 93,163 women and 89,132 men. A progressive increase in both P-ADR and D-ADR occurs with advancing age, with the P-ADR/D-ADR ratio rising from 1.2 in patients under 40 years of age to 2.65 in patients age 75 and older, in both men and women. This ratio is affected by the experience of the endoscopist. A higher volume of procedures is directly related to higher polyp detection, specifically the P-ADR.

Conclusion

As age advances, there is an increasing predominance of proximal adenomas relative to distal adenomas in both men and women, in all races. With appropriate coding, it is feasible to measure the ADR for the proximal and distal colon. Measurement of P-ADR could be an important new quality metric.