Younger age at presentation of acquired haemophilia A in Asian countries: a single-centre study and systematic review

Acquired haemophilia A is a rare bleeding disorder caused by autoantibodies against factor VIII (FVIII). There is a scarcity of acquired haemophilia A studies from Asian countries. The aim of this study was to evaluate clinical characteristics and outcomes of acquired haemophilia A among Asian populations. Data were collected from a retrospective case series and combined with a systematic review. The case series included all patients with acquired haemophilia A from 1999 to 2012 at Chiang Mai University Hospital. The systematic review searched MEDLINE and EMBASE databases for relevant keywords. A total of 111 patients were reviewed in this study (including 26 patients from the present series). There were 56 male (50.5%) and 55 female (49.5%) patients. We compared the demographic data with ECAH2 and UKHCDO studies. The weighted mean (SD) age at diagnosis was 58.10 (16.96) years compared with 75.70 (14.47) years in the European series (absolute difference 17.6 years, 95% confidence interval [CI] 14.20–20.99, P = 0.025). The mean (SD) FVIII activity was 2.97 (3.81) IU dL(−1) and the mean (SD) FVIII inhibitor titre was 26.35 (399.16) BU mL(−1). Fifty-six per cent of the patients underwent immunosuppression with steroids alone. The pool complete remission rate was comparable to the European studies, at 67.2% vs. 66.6% respectively (absolute difference 0.7, 95% CI 0.18 to 1.22, P = 0.99). This study reveals a novel finding of younger age at diagnosis of acquired haemophilia A among Asian patients.