MUC1 and idiopathic pulmonary fibrosis: Moreover, in patients with high baseline KL-6 levels (≥ 500 U/mL; n = 62), the DP group showed higher changes in KL-6 levels over 1 month ([absolute] 108.4 vs. − 40.2 U/mL, p = 0.023; [relative] 7.7 vs. − 3.6%, p = 0.021) than the no-DP group (Fig. 2B); however, there were no differences in KL-6 levels (baseline and changes over 1 month) between the two groups among patients with IPF with low baseline KL-6 levels (< 500 U/mL; n = 15).