Risk of recurrent venous thromboembolism in patients with the factor V Leiden (FVR506Q) mutation: effect of warfarin and prediction by precipitating factors. East Anglian Thrombophilia Study Group.
Three cohorts of patients with the factor V Leiden mutation were recruited independently (heterozygotes, homozygotes and combined thrombophilia). The antithrombotic efficacy of oral anticoagulation and the predictive value for recurrence of an idiopathic as opposed to a precipitated first event were determined. Idiopathic first events occurred at an older age than precipitated events (43 v 26 years, LR = 23.31, P < 0.001). None of the patients had a recurrent event while on warfarin but the median time to recurrence after stopping warfarin was 9 years (95% CI 0.7-17.3 years). The time to recurrence was shorter when the first event was idiopathic as opposed to precipitated (3.5 v 13 years, LR = 4.76, P = 0.029). A calculation of benefit to risk of oral anticoagulation with a target INR of 2.5 does not support the use of long-term therapy in all patients with the factor V Leiden mutation following a first thrombotic event.
Baglin
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C
Brown
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K
Luddington
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R
Baglin
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T
D000293:Adolescent; D000328:Adult; D000925:Anticoagulants / Q000627:therapeutic use*; D002648:Child; D005165:Factor V / Q000235:genetics*; D005260:Female; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D012008:Recurrence; D013923:Thromboembolism / Q000188:drug therapy / Q000235:genetics*; D013997:Time Factors; D014859:Warfarin / Q000627:therapeutic use*
D000925:Anticoagulants; C095381:factor V Leiden; D014859:Warfarin; D005165:Factor V