Health Care Delivery

Testing for hypercoagulable disorders in patients with deep vein thrombosis followed by 2 years of anticoagulation is cost effective

Hypercoagulable disorders, which cause abnormal blood thickening, include antiphospholipid antibody syndrome and factor V Leiden mutation. Among patients with deep vein thrombosis (a blood clot that develops in a deep vein, usually in the leg), hypercoagulable conditions raise a substantial risk of recurrent blood clots (thrombosis). A recent study found that testing for hypercoagulable disorders in patients with deep vein thrombosis followed by 2 years of anticoagulation therapy in affected patients is cost effective. The study was supported by the Agency for Healthcare Research and Quality (K08 HS11416).

Andrew D. Auerbach, M.D., M.P.H., of the University of California, San Francisco, and his colleagues performed a cost-effectiveness analysis using a model that simulated transitions between several coagulation-related health states (for example, recurrent thrombosis or bleeding complications due to anticoagulation therapy). They compared strategies of testing or not testing for a hypercoagulable state followed by anticoagulation therapy for 6 to 36 months in a hypothetical group of patients with deep vein thrombosis (of unknown cause) who were followed for life.

Testing followed by 24 months of anticoagulation in patients with a hypercoagulable condition was more cost effective ($54,820; 23.76 quality-adjusted life years, QALYs) than usual care, which involved 6 months of anticoagulation without testing ($55,260; 23.72 QALYs). All hypercoagulable conditions were common enough and associated with a sufficient risk of clot recurrence to justify inclusion in a test panel. An initial period of 2 years of anticoagulation was preferred (less than $50,000/QALY) for most conditions, whereas lifetime anticoagulation was preferred for patients with antiphospholipid antibody syndrome ($2,928/QALY) or homozygous factor V Leiden mutation ($3,804/QALY). Models using newer evidence on recurrence suggested forgoing testing and instead anticoagulating all patients for 18 months or longer when clot recurrence rates remained high in the 3 years following initial thrombosis.

See "Cost-effectiveness of testing for hypercoagulability and effects on treatment strategies in patients with deep vein thrombosis," by Dr. Auerbach, Gillian D. Sanders, Ph.D., and Julie Hambleton, M.D., in the June 15, 2004, American Journal of Medicine 116, pp. 816-828.

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