title: Can the adenoma detection rate reliably identify low-performing endoscopists? Results of a modeling study.
abstract: BACKGROUND
  Experts have stated that adenoma detection rates (ADR) of individual endoscopists should be measured to assess colonoscopy quality.
  
  
  OBJECTIVE
  The purpose of this study was to quantify the reliability of the ADR as a quality marker.
  
  
  METHODS
  We simulated a population of endoscopists and patients using published data on adenoma prevalence and adenoma miss rates. For each endoscopist, the ADR was calculated. The proportion of ADR variance attributable to endoscopist and the area under the ROC (AUROC) curve for low-performing endoscopists (lowest quartile or decile) were also calculated.
  
  
  RESULTS
  In the base-case analysis (200 patients per endoscopist, miss rate 22 %, adenoma prevalence 24 %), only 13 % of ADR variance was attributable to endoscopist performance (AUROC up to 0.73). An ADR cutoff of <16.5 % identified approximately half of endoscopists in the lowest performance decile (test sensitivity = 53 %), but most (79 %) of the endoscopists identified by this cutoff were NOT low performers (i.e., false positives). In sensitivity analysis, increasing the number of patients per endoscopist, reducing the variance of adenoma prevalence between endoscopists (i.e., performing case-mix adjustment), and increasing the variance in performance between endoscopists all improved ADR test characteristics (AUROC up to 0.88). However, regardless of assumptions, a substantial proportion of endoscopists would be misclassified if a simple ADR cutoff were utilized.
  
  
  CONCLUSIONS
  The ADR has limited reliability as a quality marker under real-world assumptions. Simple cutoffs are likely to either be insufficiently sensitive or have high false positive rates. Future studies should identify alternative means for assessing endoscopist performance.
authors: Veterans Affairs Center for Clinical Management Research, Veterans Affairs Medical Center, 2215 Fuller Road - IIID, Ann Arbor, MI 48105, USA. sdsaini@umich.edu
authors: Sameer D
authors: SD
authors: Saini
authors: Philip
authors: P
authors: Schoenfeld
authors: Sandeep
authors: S
authors: Vijan
mesh_terms: D000236:Adenoma / Q000175:diagnosis*; D003113:Colonoscopy / Q000592:standards*; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D003198:Computer Simulation; D005189:False Positive Reactions; D006801:Humans; D008962:Models, Theoretical; D019984:Quality Indicators, Health Care; D012372:ROC Curve; D015203:Reproducibility of Results