When radiological honeycombing (≥ 5% of total lung extent) was included in the multivariate model instead of a UIP pattern, a high KL-6 level was also an independent prognostic factor (HR 3.235, 95% CI, 1.394–7.510, p = 0.006) along with age (HR 1.096, 95% CI 1.043–1.152, p < 0.001), ever-smoking (HR 3.179, 95% CI 1.458–6.933, p = 0.004)., FVC (HR 0.969, 95% CI 0.946–0.993, p = 0.011) and radiologic honeycombing (HR 2.884, 95% CI 1.311–6.344, p = 0.008). This evidence concerns the gene MUC1 and idiopathic pulmonary fibrosis.