POS1158 COMPARISON OF THE ACR/EULAR 2022 CLASSIFICATION CRITERIA AND THE EMEA (THE EUROPEAN MEDICINES AGENCY) ALGORITHM IN PATIENTS WITH ANCA-ASSOCIATED VASCULITIS (AAV)

Abstract

BackgroundThe anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs) are a group of disorders involving systemic, small-vessel vasculitis. The diseases include granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). The diagnosis of vasculitis is challenging, due to the heterogeneous nature of these diseases. In 2022, ACR/EULAR proposed new internationally standardized classification criteria for AAV (ANCA-associated vasculitis). However, the performance of the new classification criteria have not been fully verified.ObjectivesTo clarify the characteristics of the ACR/EULAR 2022 classification criteria (the 2022 criteria) in patients with AAV, by comparing those of the 2022 criteria with the existing European Medicines Agency (EMEA) algorithm.MethodsAll consecutive patients who had been newly diagnosed with AAV in Keio University Hospital between March 2012 and May 2022 were retrospectively reviewed. We reclassified them according to the EMEA algorithm and the 2022 criteria and identified their difference. We also analysed their clinical characteristics statistically.ResultsWe included 114 patients in the analysis. The mean age at diagnosis of AAV was 67.2 ± 14.3, and 70 patients (61.4%) were female. According to the EMEA algorithm, the patients were classified as EGPA in 21 patients, GPA in 43, MPA in 29, and unclassifiable in 21, while according to the 2022 criteria, they were classified as EGPA in 24, GPA in 13, MPA in 62, EGPA-MPA overlap in 1, GPA-MPA overlap in 6, and unclassifiable in 8. All 21 EGPA patients with the EMEA algorithm met the EGPA-2022 criteria. Forty three GPA patients with the EMEA were classified as EGPA in 1, GPA in 11, MPA in 24, GPA-MPA overlap in 6, and unclassifiable in 1 with the 2022 criteria. Patients who were classified as GPA according to both criteria were significantly younger (53.0 ± 18.6 vs 74.5 ± 9.9 years old, respectively, P=0.003), female dominant (54.5% vs 20.8%, P=0.056), c/PR3-ANCA positive (90.9% vs 0%, P<0.001), had frequent epistaxis (45.5% vs 0%, P=0.001), and less with interstitial lung disease (9.1% vs 58.3%, P=0.007) compared to those who were reclassified from GPA to MPA with 2022 criteria. Among the 29 MPA patients with EMEA, 26 patients also met the MPA classification criteria with 2022 criteria, and among the 21 unclassifiable patients with EMEA, 12 patients were classified as MPA. Patients who were reclassified from unclassifiable to MPA with 2022 criteria were significantly older (75.2 ± 8.7 vs 57.7 ± 5.9 years old, P=0.002), had more p/MPO-ANCA (100% vs 11.1%, P<0.001), fewer ENT lesions (0% vs 55.6%, P=0.003), and tended to have more interstitial lung disease (75.0% vs 33.3%, P = 0.056) than 9 patients who did not meet the MPA-2022 criteria. During the average observation period of 3.95 ± 2.91 years, 16 patients deceased. The 16 deceased patients were classified as GPA in 7, MPA in 6, and unclassifiable in 3 with the EMEA algorithm, while they were classified as MPA in 14, GPA-MPA overlap in 1, and unclassifiable in 1 with the 2022 criteria. Overall survival was not significantly different with the EMEA algorithm (P=0.21), whereas it was significantly shorter in patients with MPA according to the 2022 criteria (P=0.023).Figure 1.Overall Survival. (A) Based on the EMEA algorithm. (B) Based on the 2022 criteria.ConclusionAmong the cases classified as GPA or unclassifiable by the EMEA algorithm, older cases with a high rate of p/MPO-ANCA and interstitial lung disease reclassified as MPA by the 2022 criteria were detected. The 2022 criteria is also useful for prognostic prediction compared to the EMEA algorithm.