Objectives Classification criteria are biased towards classifying long-standing disease. We compared the European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR)-2019, Systemic Lupus International Collaborating Clinics (SLICC)-2012 and ACR-1997 criteria in an early (median 48 months) systemic lupus erythematosus (SLE) cohort.
Methods Patients diagnosed with SLE (n=690) or control diseases (n=401). Sensitivity, specificity of the criteria and time-to-classification were calculated. Modified classification algorithms were derived from a random 80% and validated in the remaining 20% of the dataset running multiple iterations.
Results At last assessment, sensitivities of ACR-1997, SLICC-2012 and EULAR/ACR-2019 criteria were 85.7%, 91.3% and 88.6%, with specificities 93.0%, 93.8% and 97.3%, respectively. Both SLICC and EULAR/ACR enabled earlier classification. Only 76.7% of patients with SLE met all three criteria suggesting non-overlapping groups. Notably, unclassified patients had high prevalence of British Isles Lupus Assessment Group moderate/severe manifestations (43.3%–60%) and SLICC/ACR organ damage (30%–50%). At diagnosis, criteria missed 25.6%–30.5% of patients. Modification of EULAR/ACR and SLICC algorithms to include hypocomplementaemia and/or positive anti-phospholipid antibodies as alternative entry criterion, and/or allow classification with fewer clinical criteria from multiple organs, increased their sensitivity at diagnosis (median 82.0% and 86.2%) and overall (93.7% and 97.1%) with modest decreases in specificity. Importantly, patients who were still missed by the modified criteria had lower incidence of major organ involvement, use of immunosuppressive/biological therapies and organ damage.
Conclusions The SLICC and EULAR/ACR are more sensitive than the ACR and the EULAR/ACR criteria have superior specificity in early SLE, although patients with significant disease can be missed. Combination and/or modification of the classification algorithms may enhance their sensitivity, allowing earlier classification and treatment of more patients with high disease burden.
- systemic lupus erythematosus
- autoimmune diseases
- outcomes research
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Handling editor Josef S Smolen
Contributors CA, DN and AF collected data from patient medical charts and also performed data entry. I. Genitsaridi performed part of the statistical analyses (time-to-classification, 80/20 validation of the modified criteria). AB organised the RedCap database and assisted in data analyses. EK and EP contributed in the maintenance of the Cretan Lupus Registry and assisted in data collection. I. Gergianaki contributed in the establishment of the Cretan Lupus Registry and the selection of candidate study participants. PS assisted in patient recruitment and reviewed the manuscript. DB and GB conceived and supervised the study. GB performed statistical analyses. CA and GB drafted the manuscript.
Funding The study received funding by the Hellenic Society of Rheumatology & Professionals Union of Rheumatologists of Greece (protocol number: 644), the Pancretan Health Association and the Foundation for Research in Rheumatology (FOREUM; protocol number: 016BertsiasPrecl).
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The study was approved by the Ethics Committee of the University Hospital of Iraklio (protocol no. 13960/10-10-2018) and the Ethics Committee of the ‘Attikon’ University Hospital of Athens.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request.