Performance of the Revised Classification Criteria for Systemic Autoimmune Rheumatic Diseases and Their Overlap Syndromes.

Objective We evaluated the performance of the revised classification criteria for assessing different systemic autoimmune rheumatic diseases and their overlap syndromes. Methods A total of 652 patients with or highly suspected of having systemic lupus erythematosus (SLE), systemic sclerosis (SSc), polymyositis (PM)/dermatomyositis (DM) or rheumatoid arthritis (RA) were included in this study. The 1997 revised American College of Rheumatology (ACR) and the 2019 European League Against Rheumatism (EULAR)/ACR criteria for SLE, the 1980 ACR and the 2013 ACR/EULAR criteria for SSc, the criteria by Bohan and Peter and the 2017 EULAR/ACR criteria for PM/DM, and the 1987 revised ACR and 2011 ACR/EULAR criteria for RA were used for disease classification. Results The old and new criteria and a clinical diagnosis were used to respectively classify 103, 106 and 105 SLE patients; 35, 47 and 58 SSc patients; 18, 23 and 33 PM/DM patients; and 297, 389 and 468 RA patients. Sensitivity increased from 82.9% to 92.4% in SLE, from 56.9% to 79.3% in SSc, from 54.5% to 66.7% in PM/DM, and from 62.6% to 80.8% in RA. SLE-SSc was the predominant type of clinical overlap syndrome, while SLE-RA was the most classifiable. Conclusion The revised classification criteria for all the diseases showed an improved sensitivity, and SLE-overlap syndrome was predominant, regardless of the criteria sets.