Performance of the New 2019 European Alliance of Associations for Rheumatology/American College of Rheumatology Systemic Lupus Erythematosus Classification Criteria in a Large Unicentric Cohort

Background: The recently published 2019 American College of Rheumatology/European Alliance of Associations for Rheumatology (ACR/EULAR) classification criteria for systemic lupus erythematosus (SLE) were developed to increase the reliability and identification of SLE, especially in early disease. With the emergence of several new drugs for SLE, identifying and treating patients early are more important than ever. Methods: Data of 446 SLE patients evaluated in our center between 1996–2019 and 226 controls with other autoimmune diseases evaluated between 2001–2022 were retrospectively analyzed. The sensitivity and specificity of the 2019 ACR/EULAR criteria were compared to the 2012 SLICC and the 1997 ACR criteria. Results: The 2019 ACR/EULAR criteria showed very good sensitivity (86.6%) compared to the 1997 ACR criteria (76.7%), p < 0.001, with a trend toward significance compared to the 2012 SLICC criteria (83.6%), p = 0.072. Their sensitivity remained high (87.6%) in patients with a short disease duration. The specificity of the 2019 ACR/EULAR criteria (91.2%) was statistically lower than the 2012 SLICC (96.0%) and 1997 ACR criteria (95.1%), p = 0.007 and p = 0.012, respectively, but still had a very high value. A total of 22 controls (9.7%) fulfilled at least one set of criteria (15 patients with MCTD, 5 with UCTD, and 2 with SSc). Conclusion: In this large real-life cohort, the 2019 ACR/EULAR criteria had very good performance compared to the 2012 SLICC and 1997 ACR criteria.