Table 2 The predictive power of multiple biomarkers in the diagnosis of patients with RA-ILD vs. RA-non-ILD
|  | Cut-off | AUC (95%CI) | P | Sen (95%CI) | Spe (95%CI) |  + LR (95%CI) |  − LR (95%CI) | Youden index | Z | P′ |
|---|---|---|---|---|---|---|---|---|---|---|
Age (years) |  > 49 | 0.814 (0.731–0.880) |  < 0.001 | 93.33 (85.10–97.80) | 67.95 (56.40–78.10) | 2.91 (2.10–4.00) | 0.10 (0.04–0.20) | 0.613 | 3.248 | 0.001 |
KL-6 (U/mL) |  > 373.65 | 0.749 (0.660–0.824) |  < 0.001 | 61.33 (49.40–72.40) | 78.21 (67.40–86.80) | 2.81 (1.80–4.40) | 0.49 (0.40–0.70) | 0.396 | 4.256 |  < 0.001 |
D-dimer (ng/mL) |  > 716 | 0.749 (0.660–0.824) |  < 0.001 | 59.46 (47.40–70.70) | 82.19 (71.50–90.20) | 3.34 (2.00–5.70) | 0.49 (0.40–0.70) | 0.417 | 4.196 |  < 0.001 |
CA199 (KU/L) |  > 8.01 | 0.727 (0.637–0.805) |  < 0.001 | 56.52 (44.00–68.40) | 77.36 (63.80–87.70) | 2.50 (1.50–4.30) | 0.56 (0.40–0.80) | 0.339 | 4.523 |  < 0.001 |
All |  | 0.928 (0.865–0.968) |  < 0.001 | 83.82 (72.90–91.60) | 81.63 (68.00–91.20) | 4.56 (2.50–8.30) | 0.20 (0.10–0.30) | 0.655 |  |  |