[A multicentre randomised clinical trial to evaluate the benefit of testing for thrombophilia following a first venous thromboembolism: the NOSTRADAMUS study].

It is unknown whether testing patients for thrombophilia after a first episode of venous thromboembolism (VTE) and prolonging anticoagulant treatment in those with thrombophilia is justified. The NOSTRADAMUS trial, a multicentre randomised controlled trial, is being conducted to assess whether this strategy is beneficial in terms of clinical outcomes, quality of life and costs. Patients with a first VTE will be randomly assigned to one of two groups. The first group will be tested for thrombophilia and subsequently receive the test results; those in the second group will be tested but the results will not be disclosed. A total of 1336 patients will be included. Additional anticoagulant treatment for a predefined period will be initiated in patients found to have thrombophilia, while others will receive a standard predefined duration oftreatment. Primary outcomes are the risk of recurrent VTE, clinically important bleeding and the composite outcome of both. Other outcomes include overall quality of life and costs associated with outcome measures 18 months after the initial episode of VTE.