Table 4. Prognostic factors for mortality in patients with ILD assessed using cox proportional hazards model.
| Variable | Univariate Analysis | Multivariate Analysis | ||
|---|---|---|---|---|
| HR (95% CI) | P-value | HR (95% CI) | P-value | |
| Age | 1.211 (1.002–1.465) | .048 | ||
| Male | 0.206 (0.021–1.993) | .172 | ||
| Ever smokers | 0.016 (0.000–51.983) | .317 | ||
| BMI | 0.746 (0.504–1.104) | .143 | ||
| Disease duration | 0.810 (0.581–1.130) | .215 | ||
| Interstitial lung disease | ||||
| IPF | 0.667 (0.068–6.505) | .728 | ||
| CTD | 0.857 (0.089–8.294) | .894 | ||
| Radiologic pattern | ||||
| UIP | 0.031 (0.001–598.0) | .491 | ||
| Pulmonary function | ||||
| FVC | 1.031 (0.936–1.135) | .538 | ||
| DLco | 1.011 (0.946–1.081) | .742 | ||
| TLC | 1.177 (0.903–1.535) | .229 | ||
| Six-minute walk test | ||||
| Distance | 0.988 (0.976–0.999) | .037 | ||
| Baseline SpO2 | 0.802 (0.502–1.280) | .355 | ||
| Lowest SpO2 | 0.992 (0.809–1.217) | .938 | ||
| PaO2 | 0.998 (0.929–1.072) | .955 | ||
| Baseline IL-6 | 0.992 (0.953–1.033) | .694 | ||
| *Peak IL-6 | 1.007 (1.001–1.014) | .018 | 1.007 (1.001–1.014) | .018 |
| CRP | 0.914 (0.640–1.305) | .620 | ||
| LDH | 0.999 (0.985–1.013) | .882 | ||
HR: hazards ratio; CI: confidence interval; BMI, body mass index; IPF, idiopathic pulmonary fibrosis; CTD, connective tissue disease-associated interstitial lung disease; UIP, usual interstitial pneumonia; FVC, forced vital capacity; DLco, diffusing capacity of the lungs for carbon monoxide; TLC, total lung capacity; SpO2, saturation of peripheral oxygen; PaO2, partial pressure of oxygen; IL-6, interleukin-6; CRP, C-reactive protein; WBC, white blood cell; LDH, lactate dehydrogenase.
*Peak IL-6 –highest serum level of IL-6 among sequentially measured IL-6 during follow-up.