2025 Volume 37 Issue 2 Pages 112-122
【Objective】 In 2022, American College of Rheumatology and European Alliance of Associations for Rheumatology released new classification criteria（2022 ACR/EULAR classification criteria）for anti-neutrophil cytoplasmic antibody（ANCA）associated vasculitis. Microscopic polyangiitis（MPA）and granulomatosis with polyangiitis（GPA）are known to exhibit significant ethnic differences. This study was performed to evaluate the validity of the 2022 ACR/EULAR classification criteria in Japan.
【Methods】 A retrospective review was conducted on patients diagnosed with MPA or GPA at the University of Tokyo Hospital from April 2003 to September 2022.
【Results】 Concordance between the two criteria was 38/67 patients（56.7%）. Of 19 MPO-ANCA positive patients classified as GPA by the EMA algorithm, the 2022 ACR/EULAR classification criteria classified 14 patients（73.7%）as MPA and 3 patients（15.8%）as GPA, while 2 patients（10.5%）met the criteria for both MPA and GPA. Including classification changes, relapse rates did not differ significantly by classification criteria.
【Conclusion】 There was a significant number of patients whose classification differed between the EMA algorithm and the 2022 ACR/EULAR criteria. Additionally, there were patients who met the criteria for both MPA and GPA, highlighting issues that need to be addressed in the future.
