Acquired hemophilia A: a single-center study of 165 patients.

BACKGROUND: Acquired hemophilia A (AHA) is a rare hemorrhagic disorder caused by factor (F)VIII inhibitors. The diagnosis and management of AHA remains challenging because of its rarity and heterogeneity.

OBJECTIVES: To analyze the characteristics of AHA to enhance our understanding of this disease and identify effective treatment strategies. To analyze the characteristics of AHA to enhance our understanding of this disease and identify effective treatment strategies.

METHODS: Clinical features of 165 patients with AHA from a single center between July 1997 and December 2021 were retrospectively analyzed.

RESULTS: The median age of patients at diagnosis was 45 years. The median time to diagnosis was 30 days. All 165 patients experienced bleeding, with a median bleeding score (BS) of 4 (range, 2-12). Hemostatic therapy was administered to 129 (78.2%) patients. Bleeding control was achieved in 80.0% of patients who received prothrombin complex concentrate and in 92.3% of patients who were treated with recombinant activated FVII. Of the 163 patients who received immunosuppressive therapy, 80 (49.1%) received rituximab-based therapy with a 93.3% complete remission (CR) rate, 50 (30.7%) received steroids plus cyclophosphamide with an 85.0% CR rate, and 22 (13.5%) received steroids alone with an 82.4% CR rate. Six cases relapsed after a median duration of 330 days. Immunosuppressive therapy-related adverse events were reported in 17 patients. Seven deaths were recorded. FVIII inhibitor titer of ≥15 BU/mL and BS of ≥6 were identified as significantly poor prognostic factors for CR.

CONCLUSION: Immunosuppressive therapies yield remarkably high response rates, with a CR rate exceeding 80%; notably, the regimen containing rituximab exhibits a CR rate of approximately 90%. FVIII inhibitor titer of ≥5 BU/mL and BS of ≥6 were poor predictors of CR in patients with AHA.