Clinical characteristics and prognostic factors of acquired haemophilia A in Korea

Introduction: Acquired haemophilia A (AHA) treatment involves the haemostatic treatment for acute haemorrhage and immunosuppressive therapy (IST) to eradicate FVIII inhibitory antibodies. Aim: We assessed the clinical features of AHA and analysed treatment outcomes in Korea. We further identified prognostic factors affecting treatment outcomes. Methods: Medical records of 55 patients with AHA from 18 institutions were reviewed retrospectively. Logistic and Cox regression analyses were performed to elucidate clinical factors affecting the achievement of complete remission (CR). The primary endpoint was time to CR after IST, and secondary endpoints were time to haemostasis, the achievement of CR, and overall survival (OS). Results: Among the 55 patients, 50 (91%) had bleeding symptoms. Bleeding was severe in 74% of patients. Thirty-six (72%) patients received haemostatic therapy. Of the 42 patients who received IST, 23 (52%) received steroid alone, with a 52% response rate, and 10 (25%) received a combination of steroid and cyclophosphamide, with an 83% response rate. Five (16%) patients relapsed after a median duration of 220 days. There were eight deaths. In the Cox regression analysis, the FVIII inhibitor titre ≥ 20 BU/mL was the only significant prognostic factor affecting time to CR and haemostasis. No significant difference was observed in OS based on the inhibitor titre. Conclusion: The present study demonstrated the demographic data of AHA in Korea and showed that FVIII inhibitory antibody titre was a predictor of time to achieve CR after IST.