Evaluating the Threshold Score for Classification of Systemic Lupus Erythematosus Using the EULAR/ACR Criteria.

OBJECTIVE: To evaluate whether a change in the European Alliance of Associations for Rheumatology (EULAR)/American College of Rheumatology (ACR) systemic lupus erythematosus (SLE) classification criteria threshold score affects accurate classification of SLE cases compared to disease-based control subjects. We evaluated a range of threshold scores to determine the score that maximizes the accurate classification of early SLE. METHODS: We conducted a cross-sectional study comparing SLE cases and control patients. A EULAR/ACR criteria score was calculated using baseline information. Sensitivity, specificity, positive likelihood ratios (+LRs), and negative likelihood ratios (-LRs) with 95% CIs were used to evaluate operating characteristics. Threshold scores of 6 to 12 were evaluated in subjects with early disease (ie, disease duration of ≤ 5 years). +LRs > 10 and -LRs < 0.1 provide evidence to rule in or rule out SLE. RESULTS: A total of 2764 patients were included: 1980 SLE cases who fulfilled either the ACR or Systemic Lupus International Collaborating Clinics criteria and 784 control subjects. The EULAR/ACR SLE criteria had a sensitivity of 98% (95% CI 97-98), a specificity of 99% (95% CI 98-100), a +LR of 95.5 (95% CI 48.0-190), and a -LR 0.03 (95% CI 0.02-0.03). The criteria operated well in those with early disease, in women, in men, and in White, Black, Chinese, and Filipino people. A score of 10 maximized the accurate classification of patients with early disease (+LR 174.4, 95% CI 43.8-694.6; -LR 0.03, 95% CI 0.02-0.04). An increase in the threshold score from 10 to 11 resulted in significant worsening in the -LR (threshold score 10: -LR 0.03, 95% CI 0.02-0.03 vs threshold score 11: -LR 0.05, 95% CI 0.04-0.06). CONCLUSION: The EULAR/ACR SLE classification criteria threshold score of 10 performs well, particularly among those with early disease and across sexes and ethnicities.

Serum S100A8/A9 and MMP-9 levels are elevated in systemic lupus erythematosus patients with cognitive impairment.

Objective: Cognitive impairment (CI) is one of the most common manifestations of Neuropsychiatric Systemic Lupus Erythematosus (NPSLE). Despite its frequency, we have a limited understanding of the underlying immune mechanisms, resulting in a lack of pathways to target. This study aims to bridge this gap by investigating differences in serum analyte levels in SLE patients based on their cognitive performance, independently from the attribution to SLE, and exploring the potential for various serum analytes to differentiate between SLE patients with and without CI. Methods: Two hundred ninety individuals aged 18-65 years who met the 2019-EULAR/ACR classification criteria for SLE were included. Cognitive function was measured utilizing the adapted ACR-Neuropsychological Battery (ACR-NB). CI was defined as a z-score of ≤-1.5 in two or more domains. The serum levels of nine analytes were measured using ELISA. The data were randomly partitioned into a training (70%) and a test (30%) sets. Differences in the analyte levels between patients with and without CI were determined; and their ability to discriminate CI from non-CI was evaluated. Results: Of 290 patients, 40% (n=116) had CI. Serum levels of S100A8/A9 and MMP-9, were significantly higher in patients with CI (p=0.006 and p=0.036, respectively). For most domains of the ACR-NB, patients with CI had higher S100A8/A9 serum levels than those without. Similarly, S100A8/A9 had a negative relationship with multiple CI tests and the highest AUC (0.74, 95%CI: 0.66-0.88) to differentiate between patients with and without CI. Conclusion: In this large cohort of well-characterized SLE patients, serum S100A8/A9 and MMP-9 were elevated in patients with CI. S100A8/A9 had the greatest discriminatory ability in differentiating between patients with and without CI.