Cox's proportional hazards model
| Variable | Hazard ratio | p‐value | n |
| ln (SP‐A) | 1.73 | 0.031 | 142 |
| ln (SP‐D) | 2.04 | 0.003 | 142 |
| Profusion | 1.63 | <0.001 | 141 |
| Pulmonary hypertension | 2.36 | 0.002 | 141 |
| Dyspnoea | 1.05 | 0.054 | 142 |
| TLC % pred#¶ | 1.52 | 0.039 | 142 |
| FVC % pred#¶ | 1.31 | 0.031 | 142 |
| FEV1 %pred#¶ | 1.22 | 0.009 | 142 |
| DL,CO % pred#¶ | 1.36 | 0.030 | 138 |
| Resting PA-a,O2#+ | 1.34 | 0.036 | 137 |
SP‐A: surfactant protein‐A
SP‐D: surfactant protein‐D
TLC: total lung capacity
FVC: forced vital capacity
FEV1: forced expiratory volume in one second
DL,CO: carbon monoxide diffusion capacity
PA-a,O2: alveolar-arterial oxygen gradient
% pred: % predicted
#: indicates that hazards were not proportional, and the hazard ratio listed is the 1 yr estimate, while the p‐value is the p‐value testing for proportional hazards
¶: indicates that the hazard ratio is for a 10 unit decrease
+: indicates that the hazard ratio is for a 10 unit increase