title: Ascertainment of colonoscopy indication using administrative data.
abstract: BACKGROUND
  Administrative procedure code data can estimate colonoscopy utilization; however, determining colonoscopy indication is more difficult as procedure codes do not inherently reflect the purpose (screening, surveillance, diagnosis) of the colonoscopy.
  
  
  OBJECTIVE
  To improve the reported sensitivity (70%) and specificity (72%) of a published algorithm for identifying screening colonoscopies using Veterans Health Administration (VHA) administrative data.
  
  
  METHODS
  We validated three algorithms for determining colonoscopy indication using medical records as the gold standard in a national sample of 650 patients. Algorithms used International Classification of Diseases, 9th Revision (ICD-9) and Current Procedural Terminology (CPT) codes. Medical records were manually abstracted using standardized protocols.
  
  
  RESULTS
  The best algorithm had 83% sensitivity and 76% specificity for screening indication. Over 99% of colonoscopy CPT codes corresponded to a colonoscopy in the medical record.
  
  
  CONCLUSIONS
  VHA procedure codes are very accurate for colonoscopy utilization; however, algorithms to ascertain indication have only moderate accuracy.
authors.affiliation: Center for Health Services Research in Primary Care, Durham Veterans Affairs Medical Center, Durham, NC, USA. fishe034@mc.duke.edu
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Fisher
authors.forename: Janet M
authors.initials: JM
authors.lastname: Grubber
authors.forename: John M
authors.initials: JM
authors.lastname: Castor
authors.forename: Cynthia J
authors.initials: CJ
authors.lastname: Coffman
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D003113:Colonoscopy / Q000706:statistics & numerical data*; D039702:Current Procedural Terminology; D057225:Data Mining; D019992:Databases as Topic; D057286:Electronic Health Records; D005260:Female; D006302:Health Services Research; D006801:Humans; D038801:International Classification of Diseases; D008297:Male; D008403:Mass Screening / Q000379:methods / Q000706:statistics & numerical data*; D008875:Middle Aged; D018579:Patient Selection; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013997:Time Factors; D014481:United States; D014493:United States Department of Veterans Affairs / Q000706:statistics & numerical data*
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