1. A. Bianchi Bonomi Hemophilia and Thrombosis Center and Fondazione Luigi Villa Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milan Italy
2. Department of Clinical Epidemiology Leiden University Medical Center Leiden the Netherlands
3. Department of Biomedical Datasciences Section of Medical Statistics Leiden University Medical Center Leiden the Netherlands
4. Department of Pathophysiology and Transplantation University of Milan Milan Italy