Short-term anticoagulant treatment for acute deep-vein thrombosis (DVT) or pulmonary embolism (PE) effectively reduces the risk of recurrent disease during the first 6 to 12 months of therapy. Continued anticoagulation is often not instituted because of the perception among physicians that the risk of major bleeding will outweigh the risk of new venous thrombotic episodes.
Benefit-risk analysis using the randomized EINSTEIN-EXTENSION trial, which compared continued rivaroxaban versus placebo in 1197 patients with symptomatic DVT or PE who had completed 6-12 months of anticoagulation and in whom physicians had equipoise with respect to the need for continued anticoagulation. One-year Kaplan-Meier rates and rate differences of recurrent venous thromboembolism (VTE) and major bleeding were calculated. Benefits and risks were assessed using rate differences scaled to a population size of 10000 patients treated for 1 year.
Recurrent VTE occurred in 8 (3.0%) rivaroxaban recipients and 42 (9.6%) placebo patients. In a population of 10000 patients treated for 1 year, rivaroxaban treatment would have resulted in 665 (95% CI 246-1084) fewer recurrent VTEs than placebo (number needed to treat=15). Major bleeding occurred in 4 (0.7%) and 0 patients, respectively. Rivaroxaban treatment would have resulted in 68 (95% CI 2-134) more major bleeding events than placebo (number needed to harm=147). Kaplan–Meier analysis showed early recurrent VTE reduction with rivaroxaban that continued to improve throughout treatment; major bleeding increased gradually, plateauing at ±100 days.
A clinically important benefit and a favorable benefit–risk profile of continued rivaroxaban anticoagulation was observed.