Fig. 1.

Study timeline. DLCOc = diffusion capacity for carbon monoxide corrected for haemoglobin; PF-ILD = progressive fibrosing interstitial lung disease. *The phenotype PF-ILD was established when the following conditions were met: > 10% fibrosis on the HRCT and progressive disease within 24 months of the baseline: a relative decline of FVC of 10% of predicted, a relative decline of FVC of 5–10% of predicted in combination with an increase of fibrosis or worsening of respiratory symptoms, or an increase of fibrosis on HRCT in combination with worsening of respiratory symptoms