High factor VIII, von Willebrand factor, and fibrinogen levels and risk of venous thromboembolism in blacks and whites.

Venous thromboembolism (VTE) affects more than 300,000 people in the United States each year. However, it has been estimated that current diagnostic testing fails to identify prothrombotic risk in 50% of VTE patients. This article examines the relationship between levels of the pro-coagulant proteins factor VIII (FVIII), von Willebrand factor (VWF), and fibrinogen and risk of VTE in order to assess the impact of these novel risk factors. Data were collected from patients enrolled in the matched case-control Genetic Attributes and Thrombosis Epidemiology study. Crude and adjusted conditional logistic regression models were used to assess the impact of FVIII, VWF, and fibrinogen on risk of VTE. Before adjustment for independent predictors of VTE risk, high levels of FVIII, VWF, and fibrinogen were significantly associated with increased risk of VTE in both Blacks and Whites. After adjustment for ABO type, factor VII levels, hypertension, renal disease, recent surgery, diabetes, annual household income, alcohol use, and the other proteins of interest (FVIII, VWF, and/or fibrinogen), high FVIII and VWF levels were associated with increased risk of VTE in Blacks (OR: 1.97 [1.01-3.84] and 3.39 [1.58-7.27], respectively). High FVIII only was significantly associated with risk of VTE in Whites (OR: 2.35 [1.16-4.75]). Future research into the inclusion of these protein levels in risk models for VTE could help identify persons at highest risk.