Acquired haemophilia A: A 15-year population-based review of incidence rate,patient demographics and treatment outcomes |
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Authors: | Chantal Tian Brittany Perija Rami Kotb Brett L. Houston Sara J. Israels Donald S. Houston Emily Rimmer Ryan Zarychanski |
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Affiliation: | 1. Department of Internal Medicine, University of Manitoba, Winnipeg, Canada;2. Department of Internal Medicine, University of Manitoba, Winnipeg, Canada Department of Medical Oncology and Haematology, CancerCare Manitoba, Winnipeg, Canada;3. Department of Paediatrics and Child Health, University of Manitoba, Winnipeg, Canada Department of Paediatric Haematology/Oncology, CancerCare Manitoba, Winnipeg, Canada |
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Abstract: | Introduction Acquired haemophilia A (AHA) is a rare bleeding disorder characterized by autoantibodies against coagulation factor VIII (FVIII). Estimates of AHA incidence are largely based on registry data, which may be prone to referral bias. Population-based studies can enhance our understanding of the epidemiology, presentation and outcomes of AHA. Methods We conducted a retrospective, population-based cohort study of all AHA diagnosed and treated in Manitoba, Canada over a 15-year period. Using records from the sole provincial reference laboratory, we identified all patients with FVIII inhibitors who did not have congenital haemophilia. Using a piloted case report form, patient data was ascertained from hospital and bleeding disorder clinic records. Results From 2006 to 2021, we identified 34 patients with AHA, corresponding to a population-based incidence rate of AHA of 1.78 cases per million per year. The median age at presentation was 76 years and most cases were idiopathic (79%). Almost all patients (97%) presented with bleeding, of which 58% were considered major bleeds and required haemostatic agents in 67%. Longstanding unexplained bleeding symptoms were commonly reported, suggesting delayed diagnosis. Immunosuppressive therapy (IST) was administered in 88% of patients. Remission was achieved in 79% of patients; median time to remission was 2.1 months. There were two deaths due to bleeding. No deaths due to IST were reported. Conclusion The population-based incidence of AHA in Manitoba is 1.78 cases/million/year. Bleeding is common and can be life-threatening. AHA outcomes are encouraging with the use of haemostatic agents and IST. Serious treatment-associated morbidity and mortality is uncommon. |
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Keywords: | acquired haemophilia bleeding disorders cohort study epidemiology population-based |
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