Validation of the ISTH/SSC bleeding assessment tool for inherited platelet disorders:A communication from the Platelet Physiology SSC

Background Careful assessment of bleeding history is the first step in the evaluation of patients with mild/moderate bleeding disorders, and the use of a bleeding assessment tool (BAT) is strongly encouraged. Although a few studies have assessed the utility of the ISTH-BAT in patients with inherited platelet function disorders (IPFD) none of them was sufficiently large to draw conclusions and/or included appropriate control groups. Objectives The aim of the present study was to test the utility of the ISTH-BAT in a large cohort of patients with a well-defined diagnosis of inherited platelets disorder in comparison with two parallel cohorts, one of patients with type-1 von Willebrand disease (VWD-1) and one of healthy controls (HC). Patients/Methods We enrolled 1098 subjects, 482 of whom had inherited platelet disorders (196 IPFD and 286 inherited platelet number disorders [IT]) from 17 countries. Results IPFD patients had significantly higher bleeding score (BS; median 9) than VWD-1 patients (median 5), a higher number of hemorrhagic symptoms (4 versus 3), and higher percentage of patients with clinically relevant symptoms (score > 2). The ISTH-BAT showed excellent discrimination power between IPFD and HC (0.9 <area under the curve [AUC] <1), moderate (0.7 <AUC <0.9) between IPFD and VWD-1 and between IPFD and inherited thrombocytopenia (IT), while it was inaccurate (AUC