Heterozygous carriage of factor V Leiden significantly increased the risk of recurrent venous thromboembolism (RR 1.39) compared to non-carriers, whereas the risk with prothrombin G20210A mutation was lower.
Systematic Review (n=3,208)
Yes
Does heterozygous carriage of Factor V Leiden or prothrombin G20210A mutation increase the risk of recurrent VTE in patients who have discontinued anticoagulant treatment?
Heterozygous carriage of Factor V Leiden significantly increases the risk of recurrent VTE after discontinuation of anticoagulation, while the risk with prothrombin G20210A mutation is less clear.
Effect estimate: RR 1.39 (95% CI 1.15-1.67)
Absolute Event Rate: 20.5% vs 14.4%
Factor V Leiden (FVL) and prothrombin G20210A mutation (PTM) are the two most common genetic polymorphisms known to predispose to a first episode of venous thromboembolism (VTE). However, whether these thrombophilic abnormalities are also risk factors for recurrent VTE is unclear. We conducted a systematic review of prospective studies to assess the risk of recurrent VTE associated with heterozygous carriage of each of these mutations. All randomized controlled trials and prospective cohort studies that reported the incidence of recurrent VTE in patients with and without FVL and PTM after discontinuation of anticoagulant treatment were collected and analyzed. The risk ratios (RR) and their 95% confidence intervals (CI) for recurrent VTE were calculated in heterozygous carriers of FVL or PTM and compared to those of non-carriers. Eleven studies fulfilled the inclusion criteria. Recurrent VTE occurred in 114 out of 557 heterozygous carriers of FVL (20.5%) as compared to 382 out of 2,646 non-carriers (14.4%); and in 38 out of 212 heterozygous carriers of PTM (17.9%) compared to 428 of 2,996 non-carriers (14.3%). The RR of VTE recurrence conferred by the heterozygous carriage of FVL and PTM was 1.39 (95% CI, range 1.15 to 1.67) and 1.20 (range 0.89 to 1.61), respectively, using the Mantel-Haenszel fixed-effects model; 1.45 (1.13 to 1.85) and 1.36 (1.02 to 1.82), respectively, using the Der Simonian and Laird random effects method. In symptomatic patients with VTE, heterozygous carriage of FVL is clearly associated with a definitely increased risk of recurrent thromboembolism. The risk is lower with PTM and is difficult to interpret since it varies according to the assessment method used.
Marchiori et al. (Wed,) conducted a systematic review in First episode of venous thromboembolism (VTE) (n=3,208). Heterozygous carriage of factor V Leiden (FVL) vs. Non-carriers was evaluated on Recurrent venous thromboembolism (VTE) (RR 1.39, 95% CI 1.15-1.67). Heterozygous carriage of factor V Leiden significantly increased the risk of recurrent venous thromboembolism (RR 1.39) compared to non-carriers, whereas the risk with prothrombin G20210A mutation was lower.