ORIHIME II Study: Background, Treatment Status, and Outcomes of Patients with Acquired Hemophilia A with Low Activities of Daily Living Scores or Undergoing Rehabilitation - a Japanese Health Claims Database Analysis

Background: Acquired hemophilia A (AHA) is a rare disease in which autoantibodies (inhibitors) develop against blood coagulation factor (F)VIII, resulting in significantly reduced FVIII activity, with onset of bleeding symptoms such as sudden subcutaneous hemorrhage and muscular hemorrhage. The database-based study, 'Obtain Real-World Insights of Acquired Hemophilia A Patients in Japan' (the ORIHIME study) first reported data on rehabilitation and activities of daily living (ADL) scores for patients with AHA in Japan, which had previously been scarce (Ogawa et al. Blood 2021). The need to clarify the clinical experience of patients undergoing rehabilitation and patients with low ADL scores, who are considered to have relatively poor treatment and prognosis among AHA patients, has become apparent. This study evaluated the association between patient background, medication use, and outcomes among patients with AHA who underwent rehabilitation or had low ADL scores between April 1, 2008, and October 31, 2021.

Methods: The study was conducted using the Medical Data Vision Co., Ltd. database. Patients with a diagnosis of AHA who were hospitalized and were administered immunosuppressants following admission were included. The primary endpoint examined the association of actual rehabilitation practices and total ADL score (measured using the Barthel Index) at discharge with patient background, medication use, and clinical outcomes. Total ADL score was calculated by adding together the scores for each of the following activities: eating, transferring (e.g. from bed to chair and back), ambulating, toilet use, bathing, mobility, stairs, dressing, and control of bladder and bowel movement. A score of 85 or higher corresponds with 'independence with minimal assistance' in the Barthel Index, therefore, in this analysis, participants are categorized by scores of <85 and ≥85 (Sulter et al. Stroke 1999). The risk of infection due to immunosuppressive therapy was a secondary endpoint.

Results: Overall, 427 patients were included in this study. The mean (standard deviation [SD]) age of the patients was 76.3 (11.3) years, and 264 (61.8%) were male. A total of 249 patients underwent rehabilitation following admission to hospital. The median (range) time to the start of rehabilitation from the date of admission to hospital was 10.0 (1.0-133.0) days, and a high proportion of patients had a period of <2 weeks between admission to hospital and the start of rehabilitation (n=142/249 [57.0%]). Hemostatic agents used during rehabilitation were bypassing agents in 44 cases, FVIII in two cases, and tranexamic acid in 50 cases. Of the patients who received hemostatic agents, 36/44 (81.8%) patients who received bypassing agents, 2/2 (100.0%) patients who received FVIII, and 38/50 (76.0%) patients who received tranexamic acid started rehabilitation <2 weeks after the date of admission (Table 1). The ADL score at discharge was ≥85 points in 192 patients (45.0%) and <85 points in 186 patients (43.6%). Most patients with an ADL score at discharge of ≥85 (n=144/192 [75.0%]) were discharged from the hospital to home (attending outpatient visits at the same hospital), and for patients with ADL scores of <85 at discharge, the highest proportion of patients were transferred to other hospitals (n=92/186 [49.5%]; Table 2).

Conclusions: Hemostatic agents may be necessary to start rehabilitation earlier. Post-discharge outcomes may be related to ADL scores at discharge.

Amano:Chugai Pharmaceutical Co., Ltd: Consultancy, Membership on an entity's Board of Directors or advisory committees; KM Biologics: Research Funding; Bayer, Chugai Pharmaceutical Co., Ltd., CSL Behring, Japan Blood Products Organization, KM Biologics, Novo Nordisk, Pfizer, Sanofi, Takeda: Speakers Bureau. Ioka:Chugai Pharmaceutical Co., Ltd.: Current Employment. Nosaka:Chugai Pharmaceutical Co., Ltd.: Current Employment, Current equity holder in publicly-traded company. Murakami:Chugai Pharmaceutical Co., Ltd..: Current Employment, Current equity holder in publicly-traded company. Adachi:Chugai Pharmaceutical Co., Ltd..: Current Employment. Nogami:Chugai: Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Speakers Bureau; Chugai, Sanofi, Takeda, Bayer, Novo Nordisk, CSL Behring, KMBio, Fujimoto Seiyaku, Sekisu Medical, Sysmex,: Honoraria; Chugai, Sanofi, Takeda, Bayer, Novo Nordisk, KMBio, CSL Behring, Fujimoto Seiyaku, Sekisui Medical, Sysmex, AsahiKasei: Research Funding.

Rituximab used as an immunosuppressant.