The discriminant power of bleeding history for the diagnosis of type 1 von Willebrand disease: an international, multicenter study

Objective: The aim of this study was the validation of the criteria defining a significant mucocutaneous-bleeding history in type 1 von Willebrand disease (VWD). Subjects and methods: To avoid selection bias, 42 obligatory carriers (OC) of type 1 VWD were identified from a panel of 42 families with type 1 VWD enrolled by 10 expert centers. OC were identified by the presence of an offspring and another first degree relative with type 1 VWD (affected subjects, AFF). A standardized questionnaire was administered to evaluate hemorrhagic symptoms at the time of first examination, using a bleeding score ranging from 0 (no symptom) to 3 (hospitalization, replacement therapy, blood transfusion). Sensitivity, specificity, diagnostic likelihood ratios, positive and negative predictive values for the diagnosis of type 1 VWD were calculated from the data collected in OC and in 215 controls. Results: Having at least three hemorrhagic symptoms or a bleeding score of 3 in males and 5 in females was very specific (98.6%) for the bleeding history of type 1 VWD, although less sensitive (69.1%). None of the misclassified OC had life-threatening bleeding episodes after diagnosis. Conclusions: We suggest that the use of a standardized questionnaire and bleeding score may be useful for the identification of subjects requiring laboratory evaluation for VWD.