Do factor V Leiden and prothrombin G20210A mutations predict recurrent venous thromboembolism in older patients?

BACKGROUND The value of genetic thrombophilia testing in elderly patients with an unprovoked venous thromboembolism is unclear. We assessed whether the factor V Leiden and the prothrombin G20210A mutation are associated with recurrent venous thromboembolism in elderly patients in a prospective multicenter cohort study. METHODS We genotyped the factor V Leiden and the prothrombin G20210A mutation in 354 consecutive in- and outpatients aged ≥65 years with a first unprovoked venous thromboembolism from nine Swiss hospitals. Patients and managing physicians were blinded to testing results. The outcome was recurrent symptomatic venous thromboembolism during follow-up. We examined the association between the factor V Leiden and the prothrombin G20210A mutation and venous thromboembolism recurrence using competing risk regression, adjusting for age, sex, and periods of anticoagulation as a time-varying covariate. RESULTS Overall, 9.0% of patients had a factor V Leiden and 3.7% a prothrombin G20210A mutation. The At 36 months of follow-up, patients with a factor V Leiden and a prothrombin G20210A mutation had a cumulative incidence of recurrent venous thromboembolism of 12.9% (95% confidence interval [CI] 5.1-30.8%) and 18.5% (95% CI 4.9-56.5%), respectively, compared to 16.7% (95% CI 12.5-22.1%) of patients without mutation (P=0.91 by the log-rank test). After adjustment, neither the FV Leiden (sub-hazard ratio [SHR] 0.98; 95% CI 0.35-2.77) nor the prothrombin G20210A mutation (SRH 1.15; 95% CI 0.25-5.19) was associated with recurrent venous thromboembolism. CONCLUSION Our results suggest that testing for genetic thrombophilia may not be beneficial in elderly patients with a first unprovoked venous thromboembolism