title: Thrombophilia testing patterns amongst patients with acute venous thromboembolism.
abstract: BACKGROUND
  Thrombophilia testing has limited value in determining the selection and duration of anticoagulation therapy for venous thromboembolism (VTE), yet is commonly performed. This study describes the patterns and appropriateness of thrombophilia testing in a large cohort of patients with acute VTE.
  
  
  METHODS
  This was a retrospective study of a random sample of patients with a validated diagnosis of acute VTE diagnosed between January 1, 2004 and December 31, 2010. Events were identified from administrative data and verified via manual review. Patients were grouped by thrombophilia testing status and compared on patient characteristics and thrombophilia testing results and appropriateness.
  
  
  RESULTS
  Of 1314 patients with validated VTE, 315 (24%) underwent thrombophilia testing, 62 (20%) of whom had ≥ 1 positive test. Tested patients were younger and more likely to have had a family history of VTE. Factor V Leiden (17%) and prothrombin G20210A mutation (4%) were the most commonly detected thrombophilias. Only 31 (10%) of tested patients met eligibility criteria for thrombophilia testing (i.e., at least one strong thrombophilic risk factor present) and were tested at least 90 days following unprovoked index VTE.
  
  
  CONCLUSIONS
  Thrombophilia is commonly evaluated in patients without a clear indication for testing and during times where results may be unreliable. Future studies are needed to assess interventions aimed at reducing inappropriate thrombophilia testing without adversely affecting patient outcomes.
authors.affiliation: Kaiser Permanente Colorado, Pharmacy Department, Aurora, CO, United States.
authors.forename: Melissa R
authors.initials: MR
authors.lastname: Meyer
authors.affiliation: Kaiser Permanente Colorado, Pharmacy Department, Aurora, CO, United States; University of Utah College of Pharmacy, Department of Pharmacotherapy, Salt Lake City, UT, United States.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Witt
authors.affiliation: Kaiser Permanente Colorado, Pharmacy Department, Aurora, CO, United States; University of Colorado Denver Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO, United States.
authors.forename: Thomas
authors.initials: T
authors.lastname: Delate
authors.affiliation: Kaiser Permanente Colorado, Pharmacy Department, Aurora, CO, United States; University of Colorado Denver Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO, United States.
authors.forename: Samuel G
authors.initials: SG
authors.lastname: Johnson
authors.affiliation: University of California San Francisco, Division of Hospital Medicine, San Francisco, CA, United States.
authors.forename: Margaret
authors.initials: M
authors.lastname: Fang
authors.affiliation: Kaiser Permanente Northern California, Division of Research, Oakland, CA, United States; Stanford University School of Medicine, Department of Health Research and Policy, Stanford, CA, United States.
authors.forename: Alan
authors.initials: A
authors.lastname: Go
authors.affiliation: Kaiser Permanente Colorado, Pharmacy Department, Aurora, CO, United States; University of Colorado Denver Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO, United States. Electronic address: nathan.clark@kp.org.
authors.forename: Nathan P
authors.initials: NP
authors.lastname: Clark
mesh_terms: D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D019851:Thrombophilia / Q000175:diagnosis*; D054556:Venous Thromboembolism / Q000097:blood / Q000188:drug therapy*
chemical_list: D000925:Anticoagulants
keywords: Genetic testing; Hereditary; Multiphasic screening; Thrombophilia; Thrombosis; Venous thrombosis