Validation of the 2018 (new) ENMC Classification Criteria for Dermatomyositis in Chinese Patients with Idiopathic Inflammatory Myopathies

To validate the 2018 European Neuromuscular Centre classification (ENMC) criteria, compare its performance to the 1975 Bohan Peter (B P) and 2017 European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) criteria for dermatomyositis (DM), and describe characteristics of different myositis-specific autoantibody (MSA)-positive patients defined by the ENMC-DM criteria. Medical records and data on MSAs and muscle biopsies were retrospectively obtained from 1370 Chinese patients with idiopathic inflammatory myopathy (IIM) between 2008 and 2020. Patients were diagnosed with DM by at least two rheumatologists and classified according to the ENMC-DM, EULAR/ACR, and B P criteria. Of the 1370 patients, 857, 671, 693, and 913 were diagnosed with DM using the specialists’ gold standard, ENMC-DM, EULAR/ACR, and B P criteria, respectively. Significant between-group differences were observed in the clinical symptoms, serum creatine kinase levels, and MSAs (P < 0.05). Based on muscle biopsy data, the B P criteria had the highest sensitivity (94