Abstract
Background In a joint effort, the European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR) recently proposed new criteria for the classification of systemic lupus erythematosus (SLE) with the overarching goal to identify potential participants for clinical studies. Herein, we present the first independent evaluation of these criteria in comparison with older classification grounds using an adult Scandinavian study population of confirmed SLE cases and individuals with SLE-mimicking conditions.
Methods We included 56 confirmed SLE cases meeting the 1982 ACR criteria (ACR-82) and/or the Fries ”diagnostic principle” (a positive ANA test on at least one occasion plus involvement of at least two defined organ systems) and 55 controls with possible systemic autoimmune disease, including the presence of any SLE-related autoantibody.
Results The proposed EULAR/ACR criteria showed a diagnostic sensitivity of 93% (95% confidence interval (CI), 0.830.98) compared with 83% (95% CI, 0.720.91) for the updated ACR criteria from 1997. The diagnostic accuracy of all tested classification grounds was fairly similar, achieving approximately 85%. However, the disease specificity of the EULAR/ACR criteria reached only 73% (95% CI, 0.590.83) which was comparable with the 2012 Systemic Lupus International Collaborating Clinics (SLICC) criteria, 75% (95% CI, 0.610.85), but clearly lower than for ACR-82, 94% (95% CI, 0.830.99).
Weighted scores according to the proposed EULAR/ACR criteria for each of the 111 cases with regard to their classification and final diagnosis. **p=0.0005 ***p<0.0001
Conclusions In this first independent evaluation of a limited number of cases, we found comparable results with respect to diagnostic sensitivity, specificity and accuracy regarding the SLICC-12 and the proposed EULAR/ACR classification criteria. However, their specificity for SLE appeared to be lower compared to ACR-82.
Funding Source(s): This work was supported by grants from the Swedish Rheumatism Association, the County Council of Östergötland, the Swedish Society of Medicine, the King Gustaf Vs 80 year anniversary foundation and the King Gustaf V and Queen Victorias Freemasons foundation.
