Univariate analysis of parameters used to predict mortality as part of Cox proportional hazards method for all cause (n = 170 total, deaths = 15) and respiratory mortality (n = 164, deaths = 9)
| Parameter | p value (all cause mortality) | Hazard ratios (all cause mortality) | p value (respiratory mortality) | Hazard ratios (respiratory mortality) |
|---|---|---|---|---|
| Hazard ratio = eB, the predicted multiplicative change in the hazard for a unit increase in the predictor (>1 indicates that, as the predictor increases, the hazard, i.e. mortality, also increases); 95% confidence intervals are given in parentheses. Note that these hazard ratios are for each parameter in isolation and are not additive. | ||||
| Kco = carbon monoxide transfer coefficient; FEV1 = forced expiratory volume in 1 second; BMI = body mass index. | ||||
| Upper expiratory scan (voxel index) | 0.001 | 1.039 (1.015 to 1.064) | <0.001 | 1.054 (1.022 to 1.087) |
| Lower expiratory scan (voxel index) | 0.002 | 1.048 (1.014 to 1.083) | 0.001 | 1.097 (1.032 to 1.166) |
| Kco (% predicted) | 0.002 | 0.964 (0.941 to 0.987) | 0.012 | 0.962 (0.933 to 0.993) |
| Upper inspiratory scan (voxel index) | 0.005 | 1.038 (1.010 to 1.067) | 0.001 | 1.060 (1.021 to 1.100) |
| Lower inspiratory scan (voxel index) | 0.007 | 1.051 (1.011 to 1.092) | 0.002 | 1.112 (1.033 to 1.197) |
| Age (years) | 0.016 | 1.063 (1.012 to 1.118) | 0.010 | 1.088 (1.020 to 1.160) |
| SGRQ activity score (units) | 0.021 | 1.028 (1.003 to 1.054) | 0.009 | 1.061 (1.009 to 1.115) |
| SGRQ impact score (units) | 0.097 | 1.020 (0.996 to 1.045) | 0.209 | 1.020 (0.989 to 1.052) |
| FEV1 (% predicted) | 0.158 | 0.986 (0.967 to 1.006) | 0.015 | 0.941 (0.891 to 0.994) |
| BMI (kg/m2) | 0.200 | 0.919 (0.811 to 1.042) | 0.381 | 0.936 (0.795 to 1.090) |
| SGRQ symptom score (units) | 0.303 | 1.012 (0.989 to 1.036) | 0.503 | 1.010 (0.981 to 1.040) |
| Sex | 0.332 | – | 0.331 | – |
| Smoking (pack years) | 0.861 | 0.997 (0.963 to 1.032) | 0.525 | 0.985 (0.938 to 1.033) |