Single or multiple thrombophilic defects were not associated with a higher risk of recurrent VTE during warfarin therapy compared to no defects (HR for one defect 0.7; 95% CI 0.2-2.3).
RCT (n=661)
Extended low-intensity vs conventional-intensity
Does the presence of thrombophilia increase the risk of recurrent venous thromboembolism in patients with unprovoked VTE on warfarin therapy?
The presence of single or multiple thrombophilic defects does not increase the risk of recurrent VTE in patients receiving warfarin therapy for unprovoked VTE.
Effect estimate: HR 0.7 (95% CI 0.2-2.3)
We sought to determine whether thrombophilic defects increase recurrent venous thromboembolism (VTE) during warfarin therapy. Six hundred sixty-one patients with unprovoked VTE who were randomized to extended low-intensity (international normalized ratio INR, 1.5-1.9) or conventional-intensity (INR, 2.0-3.0) anticoagulant therapy were tested for thrombophilia and followed for a mean of 2.3 years. One or more thrombophilic defects were present in 42% of patients. The overall rate of recurrent VTE was 0.9% per patient-year. Recurrent VTE was not increased in the presence of factor V Leiden (hazard ratio HR, 0.7; 95% CI, 0.2-2.6); the 20210G>A prothrombin gene mutation (HR, 0); antithrombin deficiency (HR, 0); elevated factor VIII (HR, 0.7; 95% CI, 0.1-5.4); elevated factor XI (HR, 0.7; 95% CI, 0.1-5.0), or elevated homocysteine (HR, 0.7; 95% CI, 0.1-5.3), but showed a trend to an increase with an antiphospholipid antibody (HR, 2.9; 95% CI, 0.8-10.5). Compared with patients with no thrombophilic defects, the rate of recurrence was not increased in the presence of one (HR, 0.7; 95% CI, 0.2-2.3) or more than one (HR, 0.7; 95% CI, 0.2-3.4) defect. We conclude that single or multiple thrombophilic defects are not associated with a higher risk of recurrent VTE during warfarin therapy.
Kearon et al. (Fri,) conducted a rct in Unprovoked VTE (n=661). Thrombophilia (one defect) vs. No thrombophilic defects was evaluated on Recurrent venous thromboembolism (HR 0.7, 95% CI 0.2-2.3). Single or multiple thrombophilic defects were not associated with a higher risk of recurrent VTE during warfarin therapy compared to no defects (HR for one defect 0.7; 95% CI 0.2-2.3).