Comparison of adenoma detection rate and adenoma per colonoscopy as a quality indicator of colonoscopy

Background: Although adenoma detection rate (ADR) has been proposed as a quality indicator of colonoscopies, adenomas per colonoscopy (APC) is a promising alternative to ADR, as it reflects inspection over the entire length of the colon. This study investigated the correlation between ADR and APC, and compared the efficacy of ADR and APC based on the correlation of each with the advanced adenoma detection rate (AADR). Study: Two prospectively collected databases, including the 1142 subjects who underwent screening colonoscopies by 28 colonoscopists, were retrospectively reviewed. AADR1 were definded as the proportion of participants having advanced neoplasms, and AADR2 were definded as the proportion of participants having advanced neoplasms or three or more adenomas. Pearson correlation and Steiger's z-test was used to evaluate the relationship between ADR-APC, ADR-AADR and APC-AADR. Results: The ADRs ranged from 16.67 to 66.67% (mean, 37.29%) and APCs ranged from 0.22 to 1.28 (mean, 0.65). The ADR and APC showed a significant correlation (R = 0.82; p< 0.001). The screening ADR was significantly correlated with AADR1/AADR2 (R = 0.60; p = 0.001 and R = 0.64; p< 0.001, respectively). APC was also significantly correlated with AADR1/AADR2 (R = 0.65; p< 0.001 and R = 0.77; p< 0.001, respectively). The correlation coefficient for APC-AADR2 was higher than ADR-AADR2 (0.77 versus 0.64, p = 0.04). Conclusions: Colonoscopists' ADRs and APC were significantly correlated. Moreover, as the correlation coefficient for AADR was higher with APC than it was with ADR, APC might be a better quality indicator of colonoscopy than ADR.