Table 3– Predictors of mortality in the total chronic obstructive pulmonary disease population, according to the multivariate Cox regression analysis.
| HR (95% CI) | p-value | |
| Age years | 1.034 (1.009–1.059) | 0.007 |
| PaO2 kPa | 0.860 (0.755–0.979) | 0.023 |
| TLCO % pred | 0.006 | |
| Best quartile (>51) | 0.332 (0.172–0.639) | 0.001 |
| Quartile 2 (51–37.3) | 0.515 (0.322–0.825) | 0.006 |
| Quartile 3 (37.3–27.9) | 0.711 (0.477–1.059) | 0.093 |
| Quartile 4 (<27.9) | Reference | |
| GOLD classification | 0.125 | |
| Stage I | 0.506 (0.087–2.94) | 0.448 |
| Stage II | 0.407 (0.176–0.939) | 0.035 |
| Stage III | 0.639 (0.408–1.002) | 0.053 |
| Stage IV | Reference | |
| FVC % pred | 0.989 (0.969–1.010) | 0.250 |
| FEV1/FVC | 1.015 (0.994–1.037) | 0.170 |
| RV % pred | 0.988 (0.975–1.051) | 0.079 |
| FRC % pred | 1.023 (0.999–1.048) | 0.057 |
| TLC % pred | 1.008 (0.976–1.041) | 0.633 |
| IC/TLC % | 2.15 (0.37–3.293) | 0.418 |
| PaCO2 kPa | 0.985 (0.796–1.218) | 0.887 |
| BMI kg·m−2 | 1.009 (0.970–1.036) | 0.903 |
PaO2: arterial oxygen partial pressure; TLCO; carbon monoxide transfer factor; GOLD: Global Initiative for Obstructive Lung disease; FVC: forced vital capacity; FEV1: forced expiratory volume in 1 s; RV: residual volume; FRC: functional residual capacity; TLC: total lung capacity; IC: inspiratory capacity; PaCO2: arterial carbon dioxide partial pressure; BMI: body mass index.