Background: EGPA is a rare vasculitis condition with very limited data available from real-world settings on burden and health care utilization (HCU), particularly in Japan.

Objectives: To estimate the prevalence (overall and age, gender stratified) and describe HCU and treatment patterns among Japanese EGPA patients.

Methods: This was a retrospective descriptive cohort study using a large administrative claims database covering up to more than 5 million corporate employees and their dependents (JMDC claim database) in Japan. Annual prevalence from 2005-2017 was estimated using two EGPA case definitions: a) patients with ≥1 ICD-10 code (2003 version) for EGPA (M30.1), b) patients with ≥2 ICD-10 codes for EGPA (M30.1) during the year in which prevalence was calculated. Among newly identified EGPA patients with no EGPA code in at least 12 months before, clinical burden, comorbidities, after hour visiting (AHV), all cause hospitalization, and treatment with drugs, including oral corticosteroid (OCS) use was described. OCS dose was expressed as prednisone equivalent.

Results: The total number of newly identified patients in 2006-2016 was 45 persons and the mean (SD) age was 42.3 years (SD 14.7 years). The prevalence (per 1,000,000 patients) of EGPA with case definition a) in Japan in 2017 was estimated to be 38.0. The stratified prevalence (per 1,000,000) by age was: 2.3 in the group aged <18 years, 34.0 in those aged 18-50 years, and 91.1 in those aged ≥50 years, respectively. The prevalence in females (50.0) was approximately 1.7-fold higher than that in male (28.7). The prevalence, including stratified results, with definition b) was similar to that with definition a). In the newly identified patients, 60% of patients had at least one hospitalization and 55.6% had AHV, in the year after the first observed EGPA code during the study period. Following index date, new patients were treated: 77.8% with OCS, 11.1% with Azathioprine, 8.9% with intravenous immunoglobulin, 6.7% with Cyclophosphamide, 4.4% with Methotrexate, and 2.2% with Rituximab (non mutually exclusive). The mean (SD) maximum recorded daily dose of OCS in the 12 months follow up period was 53.5 (39.9) mg in new patients. The average dose (SD) of OCS in first month and last month in new patients was 39.1 (29.0) and 9.8 mg (4.8), respectively. Among those with at least a 14-day supply of OCS, 73.1% could be classified as adherent (≥80%) based on their 1-year proportion of days covered. 6.7% of EGPA patients experienced a potentially worsening with an increase of ≥10 mg daily OCS dose prescription following a previous prescription of <10mg.

Conclusion: Analysis of the burden of disease and the use of medical resources in newly identified EGPA patients revealed that EGPA patients require hospitalizations and AHV, in addition to exposure to high doses of OCS. The appropriate medication for the treatment of EGPA to reduce burden on patients may need consider the pathophysiological state of EGPA patients.

Disclosure of Interests: KEN-EI SADA Speakers bureau: I received speaker’s fee from GSK and Astra Zeneca K.K., Yoshiki Kojo Shareholder of: GSK, Employee of: GSK, Jolyon Fairburn-Beech Shareholder of: GSK, Employee of: GSK, Keiko Sato Shareholder of: GSK, Employee of: GSK, Etsuko Hayashi Shareholder of: GSK, Employee of: GSK, Shoko Akiyama Shareholder of: GSK, Employee of: GSK, melissa van-dyke Shareholder of: GSK, Employee of: GSK