title: Different screening definitions have little impact on polypectomy rate estimates.
abstract: BACKGROUND
  Polypectomy rate is a surrogate quality indicator for screening colonoscopy. Various methods for identifying screening colonoscopies have been used and it is unclear how different definitions affect the estimated polypectomy rate.
  
  
  OBJECTIVE
  To estimate polypectomy rates and how they vary according to the definition of a screening colonoscopy, using patient- and endoscopist-reported indications.
  
  
  METHODS
  A cross-sectional analysis of endoscopists and their patients 50 to 75 years of age who underwent colonoscopy was conducted. Based on questionnaire responses, four patient indications were derived: perceived screening; perceived nonscreening; medical history indicating nonscreening; and combination of the three indications. Endoscopist indication was derived from a questionnaire completed immediately after colonoscopy. Polypectomy status was obtained from provincial physician billing records. Polypectomy rates were computed, while accounting for physician and hospital level clustering, using all four patient indications, endoscopist indication, and the agreement between patient and endoscopist indications. The effect of indications on polypectomy rate was estimated adjusting for age, sex and family history of colorectal cancer.
  
  
  RESULTS
  A total of 2134 patients and 45 endoscopists were included. The proportion of colonoscopies classified as screening according to the nine indications ranged from 32.2% to 70.9%. Polypectomy rates ranged between 22.6% and 26.2% for screening colonoscopy, and between 27.1% and 30.8% for nonscreening colonoscopy. Adjusted ORs for indication ranged between 0.74 and 0.94.
  
  
  CONCLUSIONS
  Although the proportion of colonoscopies identified as screening varied considerably among the indications, the estimated polypectomy rates were similar.
  
  
  CONCLUSIONS
  The findings suggest that the way screening is defined does not greatly affect the estimates of polypectomy rate.
authors.affiliation: Division of Clinical Epidemiology, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada.
authors.forename: Mengzhu
authors.initials: M
authors.lastname: Jiang
authors.forename: Maida J
authors.initials: MJ
authors.lastname: Sewitch
authors.forename: Lawrence
authors.initials: L
authors.lastname: Joseph
authors.forename: Alan N
authors.initials: AN
authors.lastname: Barkun
mesh_terms: D000368:Aged; D003111:Colonic Polyps / Q000473:pathology* / Q000601:surgery*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000601:surgery; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D018579:Patient Selection; D011237:Predictive Value of Tests; D012307:Risk Factors