SFTPD and interstitial lung disease: We performed both univariate and multivariate logistic regression analyses, which showed that baseline serum levels of the biomarkers KL-6, SP-D, and TGF-β1 did not influence the risk of short-term progression, as defined by the four criteria analysed separately: PPF (2022 ATS/ERS/JRS/ALAT guidelines), the PF-ILD INBUILD criteria, Polish Respiratory Society guidelines, and FVC decline ≤10%.