1. Department of Haematology, Internal Medicine; Maastricht University Medical Centre+; Maastricht The Netherlands
2. Department of Epidemiology; Maastricht University; Maastricht The Netherlands
3. Department of Haematology, Internal Medicine; Radboud University Medical Centre; Nijmegen The Netherlands
4. Central Diagnostic Laboratory, Unit for Haemostasis and Transfusion; Maastricht University Medical Centre+; Maastricht The Netherlands