Extended anticoagulation and mortality in venous thromboembolism. A meta-analysis of six randomized trials.

Data on all-cause mortality in patients with venous thromboembolism (VTE) and prolonged anticoagulation are inconclusive. The aim of this study was to compare the incidence of all-cause mortality in patients with VTE at intermediate risk of recurrence, i.e. without transient risk factors or cancer, exposed to shorter (at least three months) or longer anticoagulation. We did a systematic revue and meta-analysis of randomized clinical trials searching MEDLINE and COCHRANE bibliographic databases. A random-effects model was used to pool study results. I2 testing was used to test for heterogeneity. Six studies (5920 patients) entered in the final analysis. Mean course of anticoagulation was 7.5months in the shorter and 18.6months in the longer treatment arm. Prolonged anticoagulation was associated with a statistically significant reduction in all-cause mortality (RR 0.47, 95% CI 0.29 to 0.75; 0.8% vs 1.8%). Pulmonary embolism-related death was also lowered in the longer anticoagulation arm (RR 0.32, 95% CI 0.12 to 0.83; 0.2% vs 0.6%). Longer compared with shorter anticoagulation significantly reduced all-cause mortality in patients with VTE at intermediate risk of recurrence.