Real-world Diagnosis and Testing of Acquired Hemophilia A in Japan: A Web-based Physician Survey

Objective Acquired hemophilia A (AHA) is a rare and often severe bleeding disorder caused by autoantibodies against coagulation factor VIII (FVIII). Both the prompt diagnosis and treatment of patients with AHA are essential. Data on Japanese AHA diagnostic delay are lacking; therefore, this study aimed to determine the time to AHA diagnosis in Japan, as well as to identify factors influencing the time from presentation to diagnosis. Methods This web-based, prospective, observational study surveyed physicians in Japan who had diagnosed or treated patients with AHA. The time from bleeding onset to diagnosis was the primary endpoint, with diagnostic testing barriers as the secondary endpoints. Results Of the 322 physicians who accessed the survey, 112 were included in the study. The time from bleeding onset to referral and from referral to diagnosis was ≥8 days in 31.3% (n=35) and 23.2% (n=26) of cases, respectively. The tests most commonly conducted in-hospital were activated partial thromboplastin time (aPTT) and aPTT cross-mixing tests (85.7% and 73.2%, respectively), for which results typically took