Table 3.
Prognostic factors for the mortality in patients with IPF assessed using Cox’s proportional hazards model
| Univariate | Multivariate | |||
|---|---|---|---|---|
| Hazard ratio (95% CI) | P-value | Hazard ratio (95% CI) | P-value | |
| Age | 1.035 (1.016–1.054) | < 0.001 | 1.042 (1.021–1.064) | < 0.001 |
| Male | 0.879 (0.647–1.196) | 0.413 | ||
| Ever-smokers | 0.727 (0.554–0.954) | 0.021 | ||
| FVC | 0.963 (0.955–0.972) | < 0.001 | 0.974 (0.963–0.985) | < 0.001 |
| DLCO | 0.968 (0.960–0.976) | < 0.001 | ||
| TLC† | 0.957 (0.947–0.967) | < 0.001 | ||
| 6MWT, distance | 0.996 (0.994–0.997) | < 0.001 | 0.998 (0.997–1.000) | 0.049 |
| 6MWT, initial SpO2 | 0.794 (0.734–0.859) | < 0.001 | ||
| 6MWT, lowest SpO2 | 0.910 (0.893–0.922) | < 0.001 | 0.948 (0.923–0.974) | < 0.001 |
| Antifibrotic agents | 0.392 (0.290–0.530) | < 0.001 | 0.446 (0.324–0.615) | < 0.001 |
| HRCT pattern | < 0.001 | 0.002 | ||
| UIP | 1 | 1 | ||
| Probable UIP | 0.598 (0.446–0.802) | 0.001 | 0.781 (0.565–1.078) | 0.132 |
| Indeterminate | 0.299 (0.179–0.499) | < 0.001 | 0.431 (0.254–0.732) | 0.002 |
| Alternative | 0.725 (0.467–1.124) | 0.150 | 0.520 (0.318–0.849) | 0.009 |
IPF, idiopathic pulmonary fibrosis; CI, confidence interval; PFT, pulmonary function test; FVC, forced vital capacity; DLCO, diffusing capacity of the lung for carbon monoxide; 6MWT, six-minute walk test; SpO2, saturation of peripheral oxygen; HRCT, high-resolution computed tomography; UIP, usual interstitial pneumonia
†TLC was excluded from the multivariate analysis due to its close correlation with FVC