Table 6.
Cox regression analyses of risk factors for mortality
| Univariate analysis |
Multivariate analysis |
||||||
|---|---|---|---|---|---|---|---|
| HR | CI | p-value | HR | CI | p-value | ||
| Age | 1.038 | 1.014–1.063 | 0.002 | 1.046 | 1.007–1.086 | 0.021 | |
| Sex | 1.210 | 0.766–1.911 | 0.414 | - | - | - | |
| Smoking | 0.489 | ||||||
| Nonsmoker | 1 | ||||||
| Ex-smoker | 0.517 | 0.210–1.271 | - | - | - | ||
| Never smoker | 0.634 | 0.313–1.288 | - | - | - | ||
| Six-minute walking test | |||||||
| Walking distance | 0.997 | 0.995–0.998 | <0.001 | 0.999 | 0.996–1.002 | 0.435 | |
| Minimum saturation | 0.945 | 0.919–0.972 | <0.001 | 0.949 | 0.949–0.908 | 0.993 | |
| Pulmonary function test | |||||||
| FVC | 0.969 | 0.957–0.981 | <0.001 | 0.999 | 0.977–1.022 | 0.956 | |
| DLco | 0.965 | 0.954–0.975 | <0.001 | 0.996 | 0.978–1.014 | 0.685 | |
| Initial CT pattern | 0.168 | ||||||
| Inconsistent with UIP | 1 | - | - | ||||
| Probable UIP | 2.393 | 0.746–7.675 | 0.142 | - | - | - | |
| UIP | 2.861 | 0.894–9.161 | 0.077 | - | - | - | |
| Honeycombing | 1.459 | 0.961–2.217 | 0.076 | - | - | - | |
| Initial GAP index | 1.551 | 1.377–1.747 | <0.001 | 1.099 | 0.819–1.473 | 0.530 | |
| Antifibrotics | 2.037 | 1.329–3.120 | 0.001 | 0.497 | 0.262–0.944 | 0.033 | |
| Acute exacerbation | 5.392 | 3.698–7.859 | <0.001 | 3.703 | 2.165–6.332 | <0.001 | |
| Clinical trial participation | 0.723 | 0.293–1.789 | 0.483 | - | - | - | |
| Exposure | |||||||
| Chemicals | 1.285 | 0.715–2.310 | 0.402 | - | - | - | |
| Wood dust | 2.099 | 1.089–4.048 | 0.027 | 2.449 | 1.094–5.484 | 0.029 | |
| Metal dust | 3.772 | 0.929–15.316 | 0.063 | - | - | - | |
| Fabric dust | 0.845 | 0.267–2.675 | 0.775 | - | - | - | |
| Stone dust | 2.037 | 1.242–3.339 | 0.005 | 2.269 | 1.225–4.204 | 0.009 | |
| Family history of ILD | 0.587 | 0.186–1.852 | 0.364 | - | - | - | |
HR: hazard ratio; CI: confidence interval; FVC: forced vital capacity; DLco: diffusing capacity for carbon monoxide; CT: computed tomography; UIP: usual interstitial pneumonia; GAP: gender-age-physiology; ILD: interstitial lung disease.