title: Family history and inherited thrombophilia.
abstract: BACKGROUND
  It is a common belief that patients with venous thrombosis and a positive family history for venous thromboembolism (VTE) have an increased likelihood of having an inherited thrombophilic defect.
  
  
  METHODS
  We analyzed the relation between family history, qualified with three different methods, and thrombophilic status in 314 patients with proven VTE. A positive family history (one or more first-degree relatives with VTE) and a strongly positive family history (two or more first-degree relatives with VTE). In 118 of the patients a third, more precise method was analyzed: the family history score, which compares the observed and the expected number of first-degree family members with VTE.
  
  
  RESULTS
  Patients with a positive or strongly positive family history had a slightly increased chance of having inherited thrombophilia compared to those without a positive family history. For positive family history this was 42% vs. negative 32%, likelihood ratio 1.3 (95% confidence interval; CI 0.9-2.1) and for strongly positive family history this was 46% vs. negative 34%, likelihood ratio 1.6 (95% CI 0.7-3.3). The family history score correlated with the chance of having inherited thrombophilia [OR 1.23 per score point (95% CI 1.01-1.48)]. However, even with this method the chance of having inherited thrombophilia is lower than 50% in 97% of the cases.
  
  
  CONCLUSIONS
  Family history of VTE is not a precise tool in clinical practice to identify patients with inherited thrombophilia among patients with VTE. The family history score is more precise, but probably only useful for research purposes and not for daily practice.
authors.affiliation: Academic Medical Center Amsterdam, Vascular Medicine, Amsterdam, The Netherlands. geerte.vansluis@student.uva.nl
authors.forename: G L
authors.initials: GL
authors.lastname: van Sluis
authors.forename: M
authors.initials: M
authors.lastname: Söhne
authors.forename: D Y
authors.initials: DY
authors.lastname: El Kheir
authors.forename: M W
authors.initials: MW
authors.lastname: Tanck
authors.forename: V E A
authors.initials: VE
authors.lastname: Gerdes
authors.forename: H R
authors.initials: HR
authors.lastname: Büller
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005192:Family Health; D005260:Female; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D016017:Odds Ratio; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000235:genetics*; D019851:Thrombophilia / Q000175:diagnosis* / Q000235:genetics*; D020246:Venous Thrombosis / Q000175:diagnosis* / Q000235:genetics*