To date, few studies have assessed the validity of the 2022 ACR/EULAR classification criteria. Our aim was to assess the performance of the 2022 American College of Rheumatology/European Alliance of Associations for Rheumatology (ACR/EULAR) classification criteria for eosinophilic granulomatosis with polyangiitis (EGPA) in a well-established, multicenter cohort in Eastern China and compare it against the 1990 ACR and 2017 mepolizumab in relapsing or refractory EGPA (MIRRA) criteria.

EGPA patients diagnosed between January 2018 and March 2025 were included in the study, and the diagnosis by “an expert panel” was used as the gold standard. The sensitivity, specificity, positive/negative predictive value (PPV, NPV), accuracy and receiver operating characteristic (ROC) curves of three sets of classification criteria (1990 ACR, 2017 MIRRA and 2022 ACR/EULAR) were evaluated.

 A total of 96 EGPA patients and 163 controls including 91 cases of other types of vasculitis and 72 cases of eosinophilic disorders were enrolled. 2022 ACR/EULAR classification criteria had the highest sensitivity of 87.5% and accuracy of 94.2% compared with 1990 ACR (sensitivity at 54.2% and accuracy at 82.6%) and 2017 MIRRA (sensitivity at 50.0% and accuracy at 80.7%) criteria. However, the specificity (98.2%) was slightly lower than that of the 1990 ACR (99.4%) and 2017 MIRRA (98.8%) criteria in the entire control. Thirty-five patients (36.5%) fulfilled all three criteria, 27 patients only fulfilled 2022 ACR/EULAR criteria, none fulfilled only 1990 ACR and 2017 MIRRA criteria. The most sensitive item was eosinophilia (eosinophil ratio >10% or count ≥1×109/L), with a sensitivity of 90.6%, followed by eosinophil ratio >10% (89.6%) and eosinophil count ≥1×109/L (82.3%). Eosinophil infiltration in the vascular wall had a specificity of 98.6%, making vascular wall eosinophils the most specific item.

The 2022 ACR/EULAR classification criteria demonstrated significant improvement in sensitivity and accuracy while maintaining a relatively high level of specificity. It is noticing that these criteria should not be used for the diagnosis of EGPA.