title: [Determinants of the elevated factor VIII activity in patients following venous thromboembolism].
abstract: BACKGROUND
  Activity of factor VIII (FVIII) increased above 150% of reference range predisposes to venous thromboembolism (VTE). The aim of this study was to identify predictors of increased FVIII activity in patients following VTE.
  
  
  METHODS
  241 (38% men) patients presented due to objectively documented VTE episode at least 3 months ago were included in this study. FVIII activity was measured using a clotting assay on the analyzer BCS XP.
  
  
  RESULTS
  Among 241 patients with VTE, activity of FVIII above 150% (FVIII ≥ 150%) was observed in 96 (40%). These patients were older (p = 0.035) and their concentrations of fibrinogen and C-reactive protein (CRP) were higher by 12% and 88% (p < 0.001), respectively, compared with other patients. There was a positive correlation between FVIII and fibrinogen (r = 0.34; p < 0.001), FVIII and CRP (r = 0.30; p < 0.001). Type of treatment, time from the VTE episode and type of VTE were not associated with FVIII. Twenty patients (8%) had activity of FVIII increased above 200% (FVIII > 200%) and this group was also older (p = 0.015), more patients in that group had obesity (p = 0.015), idiopathic VTE (p = 0.043), less of them had positive family history (p = 0.010) and they were characterized by fibrinogen and CRP increased by 28% (p < 0.001) and 102% (p = 0.004), respectively, compared with patients with FVIII between 150-200%. Independent predictors of FVIII ≥ 150% were: fibrinogen (p < 0.001), bilirubin (p = 0.002), hemoglobin (p = 0.016), glucose (p = 0.040), CRP (p = 0.023), total homocysteine (p = 0.032). Fibrinogen was the only independent predictor of FVIII > 200% (p = 0.016).
  
  
  CONCLUSIONS
  The activity of FVIII in patients after VTE episode is influenced by age, concentration of fibrinogen, bilirubin, hemoglobin, glucose, CRP and homocysteine. Our results suggest the role of environmental factors, mainly inflammatory response in maintaining elevated FVIII activity following VTE.
authors.forename: Monika
authors.initials: M
authors.lastname: Lech
authors.forename: Barbara
authors.initials: B
authors.lastname: Kościelniak
authors.forename: Agata
authors.initials: A
authors.lastname: Bryk
authors.forename: Anetta
authors.initials: A
authors.lastname: Undas
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001663:Bilirubin / Q000032:analysis; D001777:Blood Coagulation; D002097:C-Reactive Protein / Q000032:analysis; D005169:Factor VIII / Q000032:analysis*; D005260:Female; D005340:Fibrinogen / Q000032:analysis; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity; D054556:Venous Thromboembolism / Q000097:blood*; D055815:Young Adult
chemical_list: D006454:Hemoglobins; D005169:Factor VIII; D005340:Fibrinogen; D002097:C-Reactive Protein; D001663:Bilirubin