Applying diagnostic criteria for type 1 von Willebrand disease to a pediatric population.

BACKGROUND: Definitive diagnosis of type 1 von Willebrand disease (VWD) remains elusive in clinical practice. Both the International Society on Thrombosis and Haemostasis (ISTH) and the Hospital for Sick Children (HSC) have proposed diagnostic criteria for type 1 VWD, which include abnormal laboratory values, significant mucocutaneous bleeding history, and/or positive family history. The objective of this study was to apply ISTH and HSC criteria to a large pediatric population previously diagnosed with type 1 VWD. We hypothesized that a substantial number of patients would not meet these diagnostic criteria. PROCEDURE: We performed a retrospective medical record review of all type 1 VWD patients at a single children's hospital. Frequencies of fit for ISTH and HSC diagnostic criteria were calculated.
RESULTS: Of 201 patients, 4.5% and 34% met the ISTH and HSC definitions, respectively. An additional 15% (ISTH) and 56% (HSC) met the definition of possible disease. For each definition, criteria for significant bleeding were most likely to be met, while criteria for abnormal laboratory values were least likely. When defined as simply VWF:Ag 5-20 IU/ml, as recently proposed by the ISTH, only 9% of patients met the definition of type 1 VWD.
CONCLUSIONS: ISTH criteria failed to identify the majority of children and adolescents who presented to medical attention with significant mucocutaneous bleeding. Further work is needed to develop diagnostic criteria with improved clinical validity in the pediatric setting.