Validation of the 2022 ACR/EULAR classification criteria for giant cell arteritis in Korean patients with giant cell arteritis

Objectives We applied the 2022 American College of Rheumatology (ACR)/European Alliance of Association for Rheumatology (EULAR) criteria to Korean patients previously diagnosed with giant cell arteritis (GCA) according to the 1990 ACR criteria and validated its clinical efficiency.Methods Nine patients with GCA were included. The proportion of patients meeting each item of the 1990 ACR criteria and the 2022 ACR/EULAR criteria were assessed.Results The median age was 65.0 years, and 77.8% of the patients were women. Seven (77.8%) patients had polymyalgia rheumatica. All nine patients were reclassified as having GCA according to the 2022 ACR/EULAR criteria. Among the 10 items of the 2022 ACR/EULAR criteria, the item contributing the most to the reclassification was elevated acute-phase reactant levels (100%), followed by new temporal headache (77.8%) and fluorodeoxyglucose positron emission tomography activity throughout the aorta (77.5%).Conclusions In this study, for the first time, we demonstrated a concordance rate of 100% between the two criteria in Korean patients previously diagnosed with GCA. Moreover, we also clarified the major contributors to the reclassification according to the 2022 ACR/EULAR criteria.