Limited sensitivity and specificity of ACR/EULAR-2019 classification criteria for SLE in JSLE? - Observations from the UK JSLE Cohort Study.

OBJECTIVES This study aimed to test the performance of the "new" American College of Rheumatology (ACR) and European League Against Rheumatism (EULAR) criteria, that include anti-nuclear antibodies (ANA) positivity as entry criterion, in juvenile-onset systemic lupus erythematosus (jSLE). METHODS Performance of the ACR/EULAR-2019 criteria were compared with Systemic Lupus International Collaborating Clinics (SLICC-2012), using data from children and young people (CYP) in the UK JSLE Cohort Study (n = 482), with the ACR-1997 criteria used as reference standard. An "unselected" cohort of CYP positive for ANA (n = 129) was used to calculate positive/negative predictive values of the criteria. RESULTS At both first and last visit, the number of patients fulfilling the different classification criteria varied significantly (p < 0.001). Sensitivity of SLICC-2012 criteria was higher when compared to ACR/EULAR-2019 at first and last visit (98% vs 94%, first visit, and 98% vs 96%, last visit; p < 0.001), when all available CYP were considered. ACR/EULAR-2019 criteria were more specific when compared to SLICC-2012 (77% vs 67%, first visit, and 81% vs 71%, last visit; p < 0.001). Significant differences between the classification criteria were mainly caused by the variation in ANA positivity across ages. In the "unselected" cohort of ANA positive CYP, ACR/EULAR-2019 criteria produced the highest false positive classification (6/129, 5%) . CONCLUSION In CYP, ACR/EULAR-2019 criteria are not superior to SLICC-2012 or ACR-1997 criteria. If classification criteria are designed to include CYP and adult populations, paediatric rheumatologists should be included in the consensus and evaluation process, as seemingly minor changes can significantly affect outcomes.