The following is a summary of the “Reclassification of Patients With Previously Diagnosed Eosinophilic Granulomatosis With Polyangiitis Based on the 2022 ACR/EULAR Criteria for Antineutrophil Cytoplasmic Antibody–Associated Vasculitis,” published in the February 2023 issue of Rheumatology by Pyo, et al.

The 2022 classification criteria for eosinophilic granulomatosis with polyangiitis  (EGPA) have been proposed by the American College of Rheumatology (ACR) and the European Alliance of Rheumatology Associations (EULAR). To determine whether there was a significant difference between the 2022 ACR/EULAR criteria and the previous criteria for EGPA, the researchers applied the new criteria to a group of Korean patients who had already been diagnosed with the disease. The 2022 ACR/EULAR criteria were used to reclassify 51 EGPA patients who had previously been classified using the 1990 ACR criteria, the 2007 European Medicines Agency algorithm, or the 2012 Chapel Hill Consensus Conference definitions. 

According to the updated EGPA criteria from the ACR and EULAR in 2022, 44 out of 51 patients (86.3%). Three of the seven patients who did not meet the 2022 ACR/EULAR criteria were reclassified as having microscopic polyangiitis (MPA), one was reclassified as having granulomatosis with polyangiitis (GPA) based on the 2022 ACR/EULAR criteria, and three were reclassified as having unclassifiable vasculitis. In addition, one patient who met the EGPA criteria also met the GPA criteria, and six patients who met the EGPA criteria also met the criteria for MPA according to the 2022 ACR/EULAR criteria for MPA.

The 2022 ACR/EULAR criteria for EGPA had an 86.3% concordance rate with the previous criteria. The exclusion of nonfixed pulmonary infiltrates from the 1990 ACR criteria for EGPA was the most crucial factor in the failure to reclassify patients as having EGPA. When reclassifying cases as unclassifiable vasculitis, it is recommended to reevaluate the presence of nonfixed pulmonary infiltrates. Patients who meet the criteria for both antineutrophil cytoplasmic antibody-associated vasculitis subtypes require further classification methods.