Type 1 von Willebrand disease - a clinical retrospective study of the diagnosis, the influence of the ABO blood group and the role of the bleeding history

This clinical retrospective study investigated the difficulties in diagnosi ng type 1 von Willebrand disease (VWD). A total of 246 patients previously diagnosed with type 1 VWD were reclassified into 'possible' type 1 VWD (pat ients with low levels of VWF adjusted for the blood group and either a sign ificant bleeding history or family history) and 'definite' type 1 VWD, requ iring low levels of von Willebrand factor (VWF), a bleeding history and inh eritance. On reclassification, only 144/246 (59%) patients had low VWF leve ls adjusted for blood group, 88/246 (36%) patients met all the criteria for 'definite' type 1 VWD and 51/246 (21%) patients were 'possible' type 1 VWD . A significant proportion of patients, 102/246 (42%), remained an indeterm inate group with blood type O, VWF levels between 35 and 50 U/dl and person al and/or family bleeding history. This subgroup might require reclassifica tion as 'not VWD'. However, a similar bleeding tendency was found in two ma tched groups of patients of blood groups O and non-O and VWF levels between 35 and 50 U/dl. These results suggest that the use of ABO adjusted ranges for VWF levels might not be essential for diagnosis, because bleeding sympt oms may depend on the VWF level regardless of the ABO type. Of the diagnost ic criteria, the bleeding history was of prime importance in the clinical d ecision to diagnose and treat type 1 VWD. These observations could help in the reconsideration of how the criteria for diagnosing type 1 VWD could be adjusted in order to maximize their clinical relevance.