Family History for Venous Thromboembolism and the Risk for Recurrence

Purpose The relevance of a family history for venous thromboembolism with regard to the likelihood for recurrence is unknown. Subjects and methods We studied 826 patients for an average of 36 months after a first unprovoked venous thromboembolism and withdrawal of oral anticoagulation. Patients with cancer, lupus anticoagulant, or deficiency of antithrombin, protein C, or protein S were excluded. The study endpoint was objective evidence of recurrent symptomatic venous thromboembolism. Results Recurrence for venous thromboembolism was recorded in 23 of 190 patients (12.1%) with a family history (at least one affected first-degree family member) and in 79 of 636 patients (12.4%) without familial thrombosis (relative risk for recurrence 1.0; 95% confidence interval, 0.7-1.6; P = .9). At 5 years, the likelihood for recurrence was 20% among patients with a family history for venous thromboembolism and 18% among those without a family history for venous thromboembolism (P = .9). Risk determinants for venous thromboembolism including factor V Leiden, factor II G20210A, and high factor VIII were not statistically different between the 2 groups. Conclusion A family history for venous thromboembolism does not segregate patients into high- or low-risk categories and is not suitable to identify patients at increased risk for recurrent venous thromboembolism.