Table 3. Analyses of predictors of mortality in patients with RA-ILD.
| Characteristics | Univariate Cox regression | Multivariate Cox regression | |||
|---|---|---|---|---|---|
| Crude HR (95% CI) | P value | Adjusted HR (95% CI) | P value | ||
| Age | 1.061 (1.008–1.117) | 0.023* | 1.081 (1.002–1.165) | 0.043* | |
| Male | 1.203 (0.545–2.652) | 0.647 | – | – | |
| Ex/current smoker | 1.449 (0.650–3.229) | 0.365 | – | – | |
| Acute exacerbation of ILD | 3.193 (1.408–7.241) | 0.005* | 6.487 (1.979–21.264) | 0.002* | |
| CPFE | 1.819 (0.758–4.365) | 0.180 | – | – | |
| Honeycombing | 2.499 (1.098–5.692) | 0.029* | 3.691 (1.053–12.936) | 0.041* | |
| Malignancy complication | 0.786 (0.268–2.304) | 0.660 | – | – | |
| HRCT pattern | |||||
| Definite UIP | 1.000 (reference) | – | – | – | |
| Probable UIP | 0.324 (0.081–1.302) | 0.112 | – | – | |
| NSIP/UIP | 0.594 (0.205–1.722) | 0.337 | – | – | |
| NSIP | 0.611 (0.071–5.285) | 0.655 | – | – | |
| %FVC | 1.005 (0.977–1.034) | 0.734 | – | – | |
| %DLCO | 0.982 (0.947–1.018) | 0.323 | – | – | |
| CPI | 1.021 (0.979–1.065) | 0.328 | – | – | |
| KL-6 | 1.000 (0.999–1.001) | 0.972 | – | – | |
| SP-D | 1.003 (1.000–1.006) | 0.019* | Not estimated | – | |
*, P<0.05. RA, rheumatoid arthritis; ILD, interstitial lung disease; HR, hazard ratio; CI, confidence interval; CPFE, combined pulmonary fibrosis with emphysema; HRCT, high-resolution computed tomography; UIP, usual interstitial pneumonia; NSIP, nonspecific interstitial pneumonia; FVC, forced vital capacity; DLCO, diffusing capacity of the lung for carbon monoxide; CPI, composite physiological index; KL-6; Krebs von den Lungen-6, SP-D; surfactant protein-D.