Risks of recurrent venous thromboembolism were reduced by a longer duration of rivaroxaban treatment (3 months compared with 6 weeks) in patients with isolated distal deep-vein thrombosis (DVT), researchers report. The risk of hemorrhage was not increased by the longer duration of anticoagulation during a 2-year follow-up period.
At 28 outpatient clinics in Italy, 402 patients who had received 6 weeks of standard-dose rivaroxaban for isolated distal DVT were randomized to rivaroxaban 20 mg daily or placebo for an additional 6 weeks. Based on a primary efficacy outcome of recurrent venous thromboembolism during 2 years of follow-up after randomization, investigators found: “Isolated distal DVT was unprovoked in 81 (40%) and 86 (43%) patients, respectively. The primary efficacy outcome occurred in 23 (11%) patients in the rivaroxaban arm and 39 (19%) in the placebo arm (relative risk 0.59, 95% confidence interval 0.36 to 0.95; P = 0.03, number needed to treat 13, 95% confidence interval 7 to 126). Recurrent isolated distal DVT occurred in 16 (8%) patients in the rivaroxaban arm and 31 (15%) in the placebo arm (P = 0.02). Proximal DVT or pulmonary embolism occurred in seven (3%) patients in the rivaroxaban arm and eight (4%) in the placebo arm (P = 0.80). No major bleeding events occurred.”