The use of mean adenoma-polyp detection rate quotient as a conversion factor with polyp detection rate to predict adenoma detection rate
Background: Adenoma detection rate (ADR) is one of the most commonly used quality indicators for colonoscopy. However, its use becomes limited in small endoscopy suites due to the required access to patient records for each endoscopist and an integrated pathology and endoscopy database. Polyp detection rate (PDR) is an alternative to ADR because of its simplified calculation that only requires variables accessible in endoscopy reports. However, little data is available comparing PDR to ADR. This study aims to calculate the adenoma-to-polyp rate quotient (APDRQ) of a tertiary hospital and to determine if a PDR of an endoscopist is a good estimate of ADR.
Methods: Records of patients who underwent screening colonoscopies from January 2010 to September 2015 at St. Luke’s Medical Center, Quezon City were reviewed. The ADRs and PDRs of each year were then compared using a paired t-test to determine any statistically significant differences between years. The APDRQ was calculated by dividing the ADR by the PDR of a particular endoscopist.
Results: A total of 2918 colonoscopy procedures were included and done by 26 endoscopists. A total of 1010 procedures detected at least one polyp and 545 procedures involved biopsy of adenomas. The mean PDR of all included endoscopists is 34.61% (range 14.29 - 57.36), while the mean ADR is 18.72 (range 4.08 – 33.33). Summary APDRQ of all procedures done from 2010-2015 is 0.51. Statistically significant differences between ADR and PDR were seen mostly when comparing data during the year 2014.
Conclusion: Using mean APDRQ may be used to approximate ADR in previous and subsequent years. PDR approximates ADR for those endoscopists with more procedures done in a particular year.