Usefulness of Polyp Detection Rate as a Quality Indicator in Colonoscopy

Background/ Aims: The adenoma detection rate (ADR) has been proposed as a quality indicator of colonoscopy; however, ADR cannot be measured easily with commonly used endoscopy reporting systems because substantial time and effort is required to acquire data from histologic assessments. The purpose of this study was to determine if polyp detection rate (PDR) could be used as a valid proxy for ADR. Methods: A total of 1,156 consecutive, asymptomatic, individuals of average risk between 50 and 75 years-of-age who underwent screening colonoscopies at four tertiary medical centers by 27 gastroenterologists were included in this study. Each individual endoscopist performed at least 10 colonoscopies during the study period. The ADR and PDR were calculated as the proportion of an endoscopist's cases with an adenoma or polyp divided by the total number of colonoscopies. Pearson's correlation coefficient and the intraclass correlation coefficient were used to determine the level of agreement between ADR and PDR. Results: The mean PDR and ADR for endoscopists was 47.4% (range, 21.7-75.0) and 36.5% (range, 13.0-66.7), respectively. There was a strong correlation between PDR and ADR (Pearson's correlation coefficient 0.94, P < 0.001) and there was also good agreement between performance quintiles defined by ADR and PDR (intraclass correlation coefficient 0.94, P < 0.001). Conclusions: PDR is a valid proxy for ADR and may be useful for quality assurance at centers where ADR cannot be easily measured.