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 9 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% had a prothrombin G20210A mutation. 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 with 16.7% (95% CI, 12.5%-22.1%) of patients without mutation (P = .91 by the log-rank test). After adjustment, neither the Factor V Leiden (sub-hazard ratio 0.98; 95% CI, 0.35-2.77) nor the prothrombin G20210A mutation (sub-hazard ratio 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.