AB1058 PERFORMANCE OF THE 2019 EULAR/ACR AND 2012 SLICC CLASSIFICATION CRITERIA FOR SLE AS DIAGNOSTIC CRITERIA
Authors: F. Crisafulli, M. Y. Md Yusof, A. Aslam, A. Barr, L. A. Bissell, S. Dass, J. Arnold, P. Intapiboon, F. Franceschini, E. M. Vital
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> 2019 EULAR/ACR Systemic Lupus Erythematosus (SLE) criteria were validated for classification from cases of established SLE compared to other diseases (sensitivity 0.96 (0.95-0.98); specificity 0.93 (0.91-0.95))<sup>1</sup>, but have not been assessed as diagnostic criteria in an undiagnosed cohort of ANA positive patients clinically suspected to have SLE. <h3>Objectives:</h3> In patients with ANA positive and symptoms suspected to represent SLE, to evaluate performance of 2019 EULAR/ACR SLE criteria against a) consultants' diagnosis of SLE after 3 years follow-up and b) consultants' treatment decision. <h3>Methods:</h3> We included all consecutive consenting patients with ANA positive ≥1:80, new symptoms of ≤1 year, and SLE treatment naïve who had been referred to a specialist lupus clinic from primary care. 2019 EULAR/ACR SLE criteria and 2012 SLICC criteria were evaluated by research fellows at the time of the enrollment (T0) and evaluated annually, or on additional visits, during a 3-years follow-up. Clinical charts (at T0, and at the visit in which patients met classification criteria or last follow up visit for those who did not meet them, T1) were anonymized and any documented diagnosis was redacted. Charts were reviewed by 4 consultants who had been independent of the patients' clinical care to assess the diagnosis (Undifferentiated CTD, Sjögren's Disease (SjD), SLE, or other) as well as confidence in diagnosis and suggested treatment decision. Inter-rater agreement was analysed by Cohen's k. <h3>Results:</h3> 141 patients were included. Baseline characteristics are reported in Table 1. At T1, SLE was diagnosed by consultants in 26 patients (18.4%); a moderate inter-rater agreement was observed (k=0.52; CI 0.31–0.72). The 2019 EULAR/ACR classification criteria were met in 36 patients (26%) and the 2012 SLICC criteria in 33 patients (23.4%). Other consultants' diagnoses were: UCTD (19.1%), SjD (8%), inflammatory arthritis (IA, 3.5%). Sensitivity, specificity, PPV, NPV of the 2019 EULAR/ACR SLE and 2012 SLICC criteria are reported in Table 2. At T1, in 21 patients (14.8%), SLE diagnosis was agreed by the consultants and 2019 EULAR/ACR SLE criteria; the consultants' suggested treatments for these patients were: immunosuppressant (IS) ± hydroxychloroquine (HCQ) in 11 cases (52.4%), HCQ alone in 9 (42.8%), and no treatment in 1 (4.8%). In 5 patients (3.5%), SLE was diagnosed by consultants but not classified by the EULAR/ACR SLE criteria; the suggested treatment from the consultants were: IS in 3 cases (60%), HCQ in 2 (40%). In 15 patients where 2019 EULAR/ACR criteria were met, consultants did not diagnose SLE (10.6%); consultants' diagnoses were: SjD (40%), UCTD (33.3%), IA (26.7%%); treatment were: 7 HCQ (46.7%; in 1 case with im steroid), 5 IS (33.3%), 1 im steroid (6.7%) and no treatment in 2 (13%). In addition to the analyses above, at T0, the consultants diagnosed 11 patients who did not meet EULAR/ACR criteria as SLE. But at T1, 6/11 (55%) of these were subsequently classified as SLE. Thus, SLE could be diagnosed earlier than using classification criteria in some patients. <h3>Conclusion:</h3> When used in a diagnostic setting, the performance of 2019 EULAR/ACR SLE criteria was less good than for classification. Patients meeting classification criteria were usually clinically diagnosed as SLE as well, but some patients with a consultant diagnosis of SLE did not meet criteria and in these cases, treatment decisions were similar to those meeting criteria. Classification criteria should be used with caution for the diagnosis when evaluating patients with suspected SLE. Future work will analyse a second cohort. <h3>REFERENCES:</h3> [1] Aringer M, et al.ARD 2019 Sep;78(9):1151-1159. <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> Francesca Crisafulli UCB, UCB, Md Yuzaiful Md Yusof Alumis, Roche, Novartis, Aurinia Pharmaceuticals, UCB, Aamir Aslam: None declared, Andrew Barr: None declared, Lesley-Anne Bissell: None declared, Shouvik Dass: None declared, Jack Arnold Alumis, Porntip Intapiboon Novartis, Amgen, Franco Franceschini: None declared, Edward M. Vital Roche, GSK, AstraZeneca, Aurinia Pharmaceuticals, Lilly, Novartis, Roche, AstraZeneca, Sandoz.