Correlation between serum YKL-40 level and clinical variables.
| Characteristics | r | p |
|---|---|---|
| Age, yrs | 0.41 | < 0.001* |
| Laboratory data | ||
| KL-6, U/ml | 0.33 | < 0.01* |
| SP-D, ng/ml | –0.10 | 0.40 |
| CPK, U/ml | 0.15 | 0.21 |
| Ferritin, ng/ml | 0.46 | < 0.001* |
| PaO2, Torr | −0.40 | < 0.001* |
| Pulmonary function | ||
| %FVC | −0.18 | 0.16 |
| FEV1.0/FVC, % | −0.04 | 0.76 |
| %DLCO | −0.41 | 0.01* |
↵* p < 0.05. KL-6: Krebs von den Lungen-6; SP-D: surfactant protein-D; CPK: creatine phosphokinase; PaO2: arterial oxygen pressure; Torr: a unit of pressure based on an absolute scale, defined as exactly 1/760 of a standard atmosphere; %FVC: predicted forced vital capacity; FEV1.0: forced expiratory volume 1.0 s.