C3 and systemic lupus erythematosus: Similarly, after adjusting for age, disease duration, C3 levels, C4 levels and anti-dsDNA antibody positivity, SLE patients with a low sUromod/eGFR index score had an increased risk of having a SLICC renal activity score ≥ 5 (OR 4.27, 95% CI 1.60 to 11.38; p = 0.004).