Measurement of adenoma detection and discrimination during colonoscopy in routine practice: an exploratory study.

Background: Measuring neoplasia yield is a priority in the quality improvement process for colonoscopy. However, neither the most appropriate quality indicator nor the standard threshold has been established.

Objective: To determine the most appropriate quality indicators to assess the yield of routine colonoscopy.

Design: Retrospective.

Setting: Population-based colorectal cancer screening program in 3 French administrative areas.

Subjects: One hundred gastroenterologists and their average-risk asymptomatic patients aged 50 to 74 years undergoing colonoscopy for positive guaiac-based fecal occult blood test results.

Main Outcome Measurements: Comparison of several indicators, mainly the adenoma detection rate (ADR) and polyp detection rate (PDR), the mean number of adenomas per colonoscopy (MNA) and mean number of polyps (MNP) and the proportion of adenomas among polyps (PAP).

Results: Correlations were good between the ADR and PDR (Pearson coefficient r = 0.88 [95% CI, 0.78-0.94]) and between MNA and MNP (r = 0.89 [95% CI, 0.79-0.94]) (P < .0001 for both). Gastroenterologists were classified as higher or lower detectors in comparison with the lower limit of the 95% confidence interval of the median value for each indicator. The MNP (MNA) provided better discrimination than the PDR (ADR). Concordance between classifications of gastroenterologists according to their MNA and MNP was excellent (κ = 0.89). PAP varied dramatically from 38% to 95% between gastroenterologists and was very poorly correlated with the ADR (r = -0.27 [95% CI, -0.54 to 0.07; P = .11]) and the MNA (r = 0.03 [95% CI, -0.29 to 0.36; P = .88]).

Limitations: Some factors influencing the neoplasia yield were not taken into account.

Conclusions: The MNP could replace the ADR for the assessment of adenoma detection in routine practice. A separate indicator, PAP, would be necessary to assess adenoma discrimination ability.