ADA and systemic lupus erythematosus: In the univariate analysis (Table 3), ADA-positive SLE patients were significantly younger compared to ADA-negative (median (IQR) 34.0 (25.9–40.8) vs 44.3 (32.7–56.3) years, p = 0.002) and with shorter disease duration (median (IQR) 4.14 (1.18–10.08) vs 9.19 (5.71–16.93, p = 0.0097).