Summary
Whether a single nucleotide polymorphism (1601 G>A) in the factor VII-activating protease
gene (FSAP Marburg I) is a risk factor for venous thromboembolism (VTE) is unclear.
We investigated the relevance of the variant with respect to recurrent VTE. 854 patients
with a first unprovoked VTE were followed for an average of 41 months after discontinuation
of anticoagulation. Study endpoint was symptomatic recurrent VTE. VTE recurred in
7 of 41 patients (17%) with and in 106 of 813 patients (13%) without the variant.
After3 years, the probability of recurrence was 20.0% (95% CI, 5.3% to 34.6%) among
patients with and 12.2% (95% CI, 9.6% to 14.8%) among those without FSAP MarburgI
(p = 0. 5). The relative recurrence risk among carriers of the variant was 1.3 (95%
CI, 0.6 to 2.8; p = 0.5) before and 1.5 (95% CI, 0.7 to 3.3; p = 0. 3) after adjustment
for potentially confounding factors. We conclude that FSAP Marburg I is, if at all,
only a mild factor for recurrent VTE. Patients with FSAP Marburg I most probably will
not benefit from extended anticoagulation.
Keywords
Venous thrombosis - risk factor - recurrence - Marburg I polymorphism