Understanding Treatment Care and Delays in Acquired Hemophilia A: A Population‐Based Study From Nova Scotia, Canada

Objectives: Acquired Hemophilia A (AHA) is a rare, potentially life-threatening bleeding disorder caused by autoantibodies against factor VIII (FVIII). We aimed to characterize patients with AHA in Nova Scotia, Canada, and assess diagnostic delays. Methods: We conducted a retrospective, population-based study of adults (≥ 18 years) with AHA treated at the central Hemophilia Treatment Center (HTC) from 2006 to 2024. Demographics, presentation, treatment, outcomes, and diagnostic timelines were reviewed. Results: Twenty-seven cases were identified, with a mean annual incidence of 1.46 per million. Median age was 74 years (Interquartile range [IQR] 63.5-80); 26% had malignancy and 22% autoimmune disease. All patients received immunosuppressive therapy, and 63% required bypassing agents. Relapsing or refractory disease occurred in 30%. The 5-year overall survival was 48%. Diagnosis was delayed ≥ 7 days in 63% of cases, with median times of 32 days (IQR 4.5-75) from first bleeding and 10 days (IQR 6-45.5) from first elevated PTT. Patients had a median of 2 (IQR 2-5) bleeding-related encounters before diagnosis. Delayed diagnoses were linked to younger age, disease severity, and rural residence. Conclusion: Despite centralized care, diagnostic delays were frequent, underscoring the need for early coagulation testing in unexplained bleeding.