Table 2.
Cox Regression Analysis of the Predictive Risk Factors for Idiopathic Pulmonary Fibrosis-related Mortality
| Variable | Univariate analysis | Multivariate analysis (Model 1) | Multivariate analysis (Model 2) | |||
|---|---|---|---|---|---|---|
|
|
|
|
||||
| HR (95% CI) | P-value | HR (95% CI) | P-value | HR (95% CI) | P-value | |
| Age (yr) | 1.03 (1.01–1.05) | 0.005b | 1.06 (1.03–1.10) | 0.001b | 1.05 (1.02–1.09) | < 0.001b |
| BMI (kg/m2) | 0.92 (0.88–0.97) | 0.003b | 1.01 (0.92–1.11) | 0.872 | 0.99 (0.92–1.06) | 0.729 |
| Sex (male) | 0.78 (0.49–1.22) | 0.270 | ||||
| Alcohol consumption | 1.24 (0.83–1.85) | 0.305 | ||||
| Smoking history | 0.84 (0.65–1.70) | 0.842 | ||||
| Initial FVC (% predicted) | 0.98 (0.97–0.98) | < 0.001b | 0.98 (0.96–0.99) | 0.004b | 0.98 (0.97–0.99) | < 0.001b |
| Prednisolone | 2.09 (1.41–3.11) | < 0.001b | 1.01 (0.48–2.42) | 0.852 | 1.23 (0.63–2.40) | 0.544 |
| Azathioprine | 3.01 (2.03–4.46) | < 0.001b | 2.79 (1.31–5.94) | 0.008b | 1.85 (0.99–3.46) | 0.056 |
| ICS/LABA | 2.13 (1.13–3.99) | 0.019b | 1.00 (0.38–2.67) | 0.997 | 1.32 (0.58–3.02) | 0.507 |
| Tiotropium | 1.13 (0.55–2.32) | 0.746 | ||||
| Acetylcysteine | 0.87 (0.59–1.29) | 0.495 | ||||
| Sildenafil | 0.90 (0.29–2.83) | 0.857 | ||||
| Warfarin | 0.44 (0.11–1.77) | 0.246 | ||||
| PPI for 2 monthsa | 0.87 (0.54–1.41) | 0.572 | ||||
| PPI for 4 monthsa | 0.47 (0.23–0.92) | 0.028b | 0.51 (0.21–1.22) | 0.130 | ||
| Duration of PPI (wk) | 0.97 (0.96–0.99) | 0.001b | 0.97 (0.95–1.00) | 0.022b | ||
| GERD | 0.40 (0.20–0.80) | 0.009b | 0.62 (0.26–1.46) | 0.274 | 0.72 (0.33–1.58) | 0.413 |
| NERD | 0.35 (0.14–0.85) | 0.021b | ||||
| ERD | 0.05 (0.00–6.73) | 0.228 | ||||
| Peptic ulcer | 1.09 (0.43–2.73) | 0.857 | ||||
| Pulmonary HTN | 4.30 (1.06–17.51) | 0.042b | 37.89 (4.10–349.89) | 0.001b | 5.45 (0.71–41.97) | 0.104 |
| HTN | 0.52 (0.30–0.90) | 0.020b | 0.55 (0.25–1.20) | 0.134 | 0.50 (0.26–0.99) | 0.046b |
| DM | 1.11 (0.69–1.78) | 0.663 | ||||
| Angina | 0.60 (0.28–1.30) | 0.194 | ||||
| CKD | 0.05 (0.00–17.88) | 0.313 | ||||
a
Categorical variables were used in the analysis.
b
P-value was below 0.05.
HR, hazard ratio; BMI, body mass index; FVC, forced vital capacity; ICS/LABA, inhaled corticosteroids/long-acting beta2-agonists; PPI, proton pump inhibitor; GERD, gastroesophageal reflux disease; NERD, non-erosive reflux disease; ERD, erosive reflux disease; HTN, hypertension; DM, diabetes mellitus; CKD, chronic kidney disease.