title: Evaluation of the predictive value of ICD-9-CM coded administrative data for venous thromboembolism in the United States.
abstract: OBJECTIVE
  To determine the positive predictive value of International Classification of Disease, 9th Revision, Clinical Modification (ICD-9-CM) discharge codes for acute deep vein thrombosis or pulmonary embolism.
  
  
  METHODS
  Retrospective review of 3456 cases hospitalized between 2005 and 2007 that had a discharge code for venous thromboembolism, using 3 sample populations: a single academic hospital, 33 University HealthSystem Consortium hospitals, and 35 community hospitals in a national Joint Commission study. Analysis was stratified by position of the code in the principal versus a secondary position.
  
  
  RESULTS
  Among 1096 cases that had a thromboembolism code in the principal position the positive predictive value for any acute venous thrombosis was 95% (95%CI:93-97), whereas among 2360 cases that had a thromboembolism code in a secondary position the predictive value was lower, 75% (95%CI:71-80). The corresponding positive predictive values for lower extremity deep-vein thrombosis or pulmonary embolism were 91% (95%CI:86-95) and 50% (95%CI:41-58), respectively. More highly defined codes had higher predictive value. Among codes in a secondary position that were false positive, 22% (95%CI:16-27) had chronic/prior venous thrombosis, 15% (95%CI:10-19) had an upper extremity thrombosis, 6% (95%CI:4-8) had a superficial vein thrombosis, and 7% (95%CI:4-13) had no mention of any thrombosis.
  
  
  CONCLUSIONS
  ICD-9-CM codes for venous thromboembolism had high predictive value when present in the principal position, and lower predictive value when in a secondary position. New thromboembolism codes that were added in 2009 that specify chronic thrombosis, upper extremity thrombosis and superficial venous thrombosis should reduce the frequency of false-positive thromboembolism codes.
authors.affiliation: Division of General Medicine, University of California, Davis, CA, USA. rhwhite@ucdavis.edu
authors.forename: Richard H
authors.initials: RH
authors.lastname: White
authors.forename: Martina
authors.initials: M
authors.lastname: Garcia
authors.forename: Banafsheh
authors.initials: B
authors.lastname: Sadeghi
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Tancredi
authors.forename: Patricia
authors.initials: P
authors.lastname: Zrelak
authors.forename: Joanne
authors.initials: J
authors.lastname: Cuny
authors.forename: Pradeep
authors.initials: P
authors.lastname: Sama
authors.forename: Harriet
authors.initials: H
authors.lastname: Gammon
authors.forename: Stephen
authors.initials: S
authors.lastname: Schmaltz
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Romano
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006785:Hospitals, University; D006801:Humans; D038801:International Classification of Diseases; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism; D012189:Retrospective Studies; D013923:Thromboembolism; D014481:United States / Q000453:epidemiology; D054556:Venous Thromboembolism / Q000453:epidemiology*; D020246:Venous Thrombosis