Direct oral anticoagulants (DOACs) are replacing vitamin K antagonists (VKA) for most patients with atrial fibrillation (AF) and venous thromboembolism. The four currently available DOACs were compared with VKA in phase III randomised controlled trials that collectively included over 100,000 patients. The results show that DOACs, at a fixed dose without laboratory monitoring, are at least as effective as VKA therapy and reduce the risk of major bleeding, including a 50% risk reduction of intracranial bleeding . As a consequence, DOACs are now recommended over VKA in the international guidelines . Yet, after regulatory approval there were concerns that the trial results may not apply to the patients in our daily clinical practice that generally have more comorbidities than a standard trial population. This led to a broad call for post-authorisation (phase IV) studies that were soon referred to as Real World studies, suggesting that the phase III studies originate from a world that is unreal.
Coppens M. Neth Heart J. 2017, 3 August.