title: Impact of thrombophilia screening on venous thromboembolism management practices.
abstract: BACKGROUND
  It is unclear whether thrombophilia testing provides any further information on risk of recurrence or guidance in management of patients with a first episode of idiopathic venous thromboembolism (VTE). Furthermore, after the introduction to clinical practice of clinical prediction rules, thrombophilia screening could be less relevant in anticoagulation decision making. We assessed the potential impact of thrombophilia screening on the decision of maintaining anticoagulation beyond the initially planned anticoagulation period in patients with an unprovoked VTE, before and after the introduction of a clinical prediction rule into practice.
  
  
  METHODS
  We conducted a single center, retrospective cohort study of consecutive patients with a diagnosis of unprovoked VTE, including a study period of 12years. Two groups were compared, before and after 2008.
  
  
  RESULTS
  We included 1033 patients of which 85.2% were tested for thrombophilia and 26.2% were identified with any thrombophilia. A similar proportion of patients continued on anticoagulation after 6months (54.1% vs 57.1%, respectively). The proportion of patients continuing anticoagulation based on the thrombophilia screen remained small (13.9% vs 12.7%, respectively). Continuing anticoagulation beyond the initial period planned resulted in a 75% risk reduction in VTE recurrence, independent of the presence of thrombophilia (HR 0.25, 95% CI 0.12-0.55; P<0.001).
  
  
  CONCLUSIONS
  Thrombophilia screening continues to have little relevance in clinical decision making for anticoagulation. Prolonging anticoagulation beyond 6months in an at-risk population decreased the risk of VTE recurrence regardless of their thrombophilia status.
authors.affiliation: Department of Medicine, Division of Hematology, University of Western Ontario, London, ON, Canada.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Garcia-Horton
authors.affiliation: Department of Medicine, Division of Hematology, University of Western Ontario, London, ON, Canada.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kovacs
authors.affiliation: Department of Medicine, Division of Hematology, University of Toronto, Toronto, ON, Canada.
authors.forename: Jameel
authors.initials: J
authors.lastname: Abdulrehman
authors.affiliation: Department of Family Medicine, University of Western Ontario, London, ON, Canada.
authors.forename: Jay E
authors.initials: JE
authors.lastname: Taylor
authors.affiliation: Department of Medicine, Division of Hematology, University of Western Ontario, London, ON, Canada.
authors.forename: Shobha
authors.initials: S
authors.lastname: Sharma
authors.affiliation: Department of Medicine, Division of Hematology, University of Western Ontario, London, ON, Canada; Department of Epidemiology and Biostatistics, University of Western Ontario, London, ON, Canada. Electronic address: alejandro.lazolangner@lhsc.on.ca.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Lazo-Langner
mesh_terms: D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012189:Retrospective Studies; D055502:Secondary Prevention; D019851:Thrombophilia / Q000150:complications / Q000175:diagnosis*; D054556:Venous Thromboembolism / Q000150:complications / Q000188:drug therapy* / Q000517:prevention & control
chemical_list: D000925:Anticoagulants