Appropriateness of Immunosuppression and Blood Product Utilization in Acquired Hemophilia A: A Multicentre Provincial Practice Audit

Introduction: Acquired hemophilia A (AHA) is a life-threatening bleeding disorder associated with significant morbidity and mortality. Despite publication of international consensus guidelines, quality of care and guideline adherence have not been examined. While some jurisdictions have reference centres for AHA management, in Canadian provinces outside of Quebec, AHA is managed in both hemophilia treatment centres (HTCs) and community hospitals. We performed a multicentre practice audit in a Canadian province to assess use of immunosuppressive therapy (IST), blood product utilization, and evaluate treatment burden and outcomes. Methods: We included adults diagnosed with AHA (January 2000-December 2021) in Alberta, Canada, and examined the following quality of care indicators: delayed IST initiation from diagnosis, corticosteroid use alone in high-risk AHA (FVIII 20 BU/ml), cyclophosphamide use in low-risk patients (FVIII ≥0.01 IU/ml and inhibitor ≤20 BU/ml), prolonged cyclophosphamide use (>6 weeks), and inappropriate use of plasma, intravenous immunoglobulin (IVIG) and hemostatic products. Outcome measures included response, length of stay (LOS) and 30-day readmission. We evaluated treatment burden including frailty syndromes, increased level of care and hospitalization for treatment-related adverse events. Results: Of the 38 patients diagnosed with AHA, 25 (66%) were female, the median age was 74 years (IQR 61-81), and median Charlson comorbidity index was 5 (IQR 3-7). Cardiovascular comorbidities were common, including venous thromboembolism (5; 13%), atrial fibrillation (5; 13%), and myocardial infarction (4; 11%). Fifteen (39%) had ≥1 frailty syndromes, including functional dependence (6; 16%), dementia (6; 16%), falls/fractures (5; 13%), and depression/anxiety (3; 8%). Five (13%) patients required higher levels of care (long term care placement) following discharge. Twenty-one (55%) patients had high-risk disease and 17 (45%) had low-risk. In those with low-risk disease, 11 (29%) had inhibitor titres 5-20 BU/ml and 6 (16%) had inhibitors