Cost-effectiveness of testing for hypercoagulability and effects on treatment strategies in patients with deep vein thrombosis.

PURPOSE Among patients with deep vein thrombosis, hypercoagulable conditions impart a substantial risk of recurrent thrombosis. We sought to determine the cost-effectiveness of testing for these disorders, as well as which tests should be selected and how results should be used. METHODS Using a Markov state-transition model, strategies of testing or not testing for a hypercoagulable state followed by anticoagulation for 6 to 36 months were compared in a hypothetical cohort of patients with apparently idiopathic deep vein thrombosis who were followed for life. Strategies were compared based on lifetime costs, quality-adjusted life-years (QALYs), and marginal cost-effectiveness. RESULTS In the base case, testing followed by 24 months of anticoagulation in patients with a hypercoagulable condition was more cost-effective ($54,820; 23.76 QALYs) than usual care, which comprised 6 months of anticoagulation without testing ($55,260; 23.72 QALYs). All hypercoagulable conditions tested were common enough and associated with a sufficient risk of recurrence to justify inclusion in a test panel. Twenty-four months of initial anticoagulation was preferred (<$50,000/QALY) for most conditions, whereas lifetime anticoagulation was preferred for patients with antiphospholipid antibody syndrome ($2928/QALY) or homozygous factor V Leiden mutation ($3804/QALY). Models using newer evidence on recurrence suggested 18 to 36 months of anticoagulation without testing as the preferred approach. CONCLUSION Testing for hypercoagulable disorders in patients with idiopathic deep vein thrombosis followed by 2 years of anticoagulation in affected patients is cost-effective. A simpler approach of treating all patients with prolonged anticoagulation without testing is justified if data confirm the persistent risk of recurrent thrombosis.