Simplifying Measurement of Adenoma Detection Rates for Colonoscopy

Adenoma detection rate (ADR) is the colonoscopy quality metric with the strongest association to interval or "missed" cancer. Accurate measurement of ADR can be laborious and costly.

Our aim was to determine if administrative procedure codes for colonoscopy and text searches of pathology results for adenoma mentions could estimate ADR.

We identified US Veterans with a colonoscopy using Current Procedure Terminology (CPT) codes between January 2013 and December 2016 at ten Veterans Affairs sites. We applied simple text searches using Microsoft SQL Server full-text searches to query all pathology notes for "adenoma(s)" or "adenomatous" text mentions to calculate ADRs. To validate our identification of colonoscopy procedures, endoscopists of record, and adenoma detection from the electronic health record, we manually reviewed a random sample of 2000 procedure and pathology notes from the 10 sites.

Structured data fields were accurate in identification of colonoscopies being performed (PPV = 0.99; 95% CI 0.99-1.00) and identifying the endoscopist of record (PPV of 0.95; 95% CI 0.94-0.96) for ADR measurement. Simple text searches of pathology notes for adenoma mentions had excellent performance statistics as follows: sensitivity 0.99 (95% CI 0.98-1.00), specificity 0.93 (95% CI 0.92-0.95), NPV 0.99 (95% CI 0.98-1.00), and PPV 0.93 (0.91-0.94) for measurement of ADR. There was no clinically significant difference in the estimates of overall ADR vs. screening ADR (p > 0.05).

Measuring ADR using administrative codes and text searches from pathology results is an efficient method to broadly survey colonoscopy quality.