Associations between KL-6 serum level and spirometry results:
(figure 1) shows a significant inverse correlation between serum levels of KL-6 and predicted FEV1 (%Pred) (r = − 0.7056, P = 0.000), and also a significant inverse correlation between serum levels of KL-6 and FVC (%Pred) (r = − 0.7745, P = 0.000).