On multivariate analysis, a high KL-6 level was independently associated with poor prognosis (hazard ratio [HR], 2.984; 95% CI, 1.227–7.257; P = 0.016); In addition, older age, male sex, lower FVC, and a UIP pattern were also independently associated with poor prognosis. Here, MUC1 is linked to idiopathic pulmonary fibrosis.