This is a phase 4 cohort prospective, open, national, multicentre study that collects data on history of patients treated chronically with anticoagulant drugs, including the novel direct oral anticoagulants (DOACs). The Registry is designed solely for observational purposes and is not intended to have any influence on the treatment of the single patients included. Patients are included when they start the anticoagulant treatment, whatever the drug used, or when they shift from a vitamin K antagonist (VKA) drug to one of the novel direct oral anticoagulants, provided that the therapy is expected to last at least 3 months. The general aims of the study are to provide a better evaluation of efficacy and safety of different treatment options, and to improve our understanding of the risks/benefits of the various anticoagulant drugs and the different therapy options. The Registry is open to the participation of clinical centres or individual professionals (now called Participants) that are involved with management of anticoagulated patients.