MUC1 and idiopathic pulmonary fibrosis: Ohshimo et al. studied 77 patients with IPF and reported that a high KL-6 level (≥ 1300 U/mL) was an independent risk factor for the development of AE (HR = 11.8, 95% CI 1.43–97.8, P = 0.022) when adjusted for age, sex, smoking history, and treatment43.