Comparison of the diagnostic criteria for progressive pulmonary fibrosis (PPF) in the ATS/ERS 2022 idiopathic pulmonary fibrosis and PPF guideline update and the INBUILD progressive fibrosing interstitial lung disease (PFILD) randomised control trial inclusion criteria

ERS/ATS PPF criteria [3] (any 2 criteria)INBUILD trial PFILD criteria [8]
Forced vital capacityAbsolute decline ≥5%Relative decline >10%
OR 5–10% and any of the below criteria
SymptomsWorsened respiratory symptomsWorsened respiratory symptoms
DLCOAbsolute decline ≥10%Not included
RadiologyWorsened fibrosis on HRCTWorsened fibrosis on HRCT
Time-period decline/investigations must be within12 months24 months

ATS: American Thoracic Society; ERS: European Respiratory Society; DLCO: diffusing capacity of the lung for carbon monoxide; HRCT: high-resolution computed tomography.