In an unadjusted Cox proportional hazards model, high KL-6 levels (≥ 800 U/mL), lower lung function (FVC), and lower the minimum oxygen saturation during the 6MWT, diagnosis of IPF and use of antifibrotics, were significantly related to disease progression (Table 3). This evidence concerns the gene MUC1 and idiopathic pulmonary fibrosis.