MUC1 and idiopathic pulmonary fibrosis: In a multivariable analysis of data from 62 subjects with IPF who were treated with antifibrotic therapy and had baseline KL-6 levels ≥500 U·mL−1, higher relative changes in KL-6 levels over 1 month were associated with disease progression (relative decline in FVC % pred ≥10% or DLCO % pred ≥15%, acute exacerbation or death within 6 months of starting antifibrotic therapy) [25].