PS1108 CLINICAL FEATURES AND TREATMENT OUTCOMES OF ACQUIRED HEMOPHILIA A IN KOREA: RETROSPECTIVE ANALYSIS
Authors: S.Y. Hyun, H.‐J. Shin, S.‐S. Yoon, J.H. Moon, J.J. Han, S.‐M. Bang, H.‐Y. Yhim, S.‐H. Kim, D. Oh, Y.R. Do, Y. Park, C.W. Choi, J.‐H. Lee, W.S. Lee, K.S. Lee, J.S. Kim
Journal: HemaSphere (2019)

Background: Acquired hemophilia A (AHA) is a rare disease caused by depletion or suppression of coagulation factor FVIII by autoimmune antibodies. Factor VIII inhibitory antibodies neutralize the activity of Factor VIII and, if not properly treated, can lead to life‐threatening hemorrhage or death, with mortality rates as high as 9–22%. There is no report on the incidence and treatment of AHA in Korea. Only a small number of cases have been reported. Aims: The purpose of this study was to evaluate the clinical characteristics and treatment outcome of patients with AHA in Korea. Methods: Patients diagnosed with AHA from January 2006 to May 2016 were enrolled from the 15 institutions in Korea. The diagnostic criteria for AHA were defined as FVIII: C 50% or less and FVIII inhibitory antibody was 0.6 BU/mL or more. A total of 55 patients were enrolled and their medical records were analyzed retrospectively Results: Median age was 66 (18–86) years old. In epidemiology, idiopathic was 38% and associated disease was 62%. In epidemiology, 21 patients (38%) were idiopathic and 34 (62%) patients had associated diseases. Associated disease was followed by autoimmune disease (19%), surgery of other disease (13%), infection (13%), pregnancy/postpartum (12%) and hematologic malignancy (12%). The mean FVIII:C activity at diagnosis was 2.69 ± 2.97%, and 14 (26%) patients were less than 1%. The mean titer of FVIII inhibitor was 24.38 ± 34.87 U, and 55 (45%) patients had less than 10 BU. The time from the onset of symptoms to diagnosis was 15.5 (0–100) day, and the time from the first contact with the hematologist to the diagnosis was 3.0 (0–74) day. Overall, the time from symptom onset to diagnosis was relatively long. The sites of bleeding were subcutaneous/skin (83%), muscular (43%), gastrointestinal (21%), mucosal (19%), retroperitoneal (17%), genitourinary (4%), respectively. The severity of bleeding was major in 39 of 55 (71%), and a mean of 14.32 ± 3.332 U red blood cells were transfused per patient who experienced major bleeding. Of the 30 patients who treated for hemostasis, 14 received bypassing agents and 16 received factor VIII concentrates as 1 st line hemostatic therapy. The efficacy of the bypassing agent was 86%, which was statistically higher than that of FVIII concentrates (31%) (p &lt;0.05). As immune‐suppressive therapy to eradicate the FVIII antibody, 18 patients (33%) were treated with glucocorticoid alone, and 12 patients (22%) with glucocorticoid and cyclophosphamide combination therapy. The response rate (CR + PR) of glucocorticoid therapy alone was 61%, and the combination of glucocorticoid and cyclophosphamide was 91% (p &lt;0.05). Adverse events were not different between the two groups. The overall survival rate at 1 year was 81.6% and 6 patients died. The causes of death were infection (4 cases) and intracranial hemorrhage (2 cases). Summary/Conclusion: The clinical features of AHA in Korea were not significantly different from the previously published registry data. However, it is considered that the time from symptom onset to diagnosis was relatively long because lack of awareness of AHA. In addition, due to financial problems including national health insurance, only ∼30% of patients were treated with bypassing agent as primary hemostatic therapy. It is necessary to establish more effective treatment strategies in Korea based on the large‐scale prospective analysis of Korean AHA patients.