Table 1.

Definition criteria for progressive pulmonary fibrosis [8]

1) Worsening respiratory symptoms
2) Functional decline measured through PFT (one of the following)	Absolute decline in FVC > 5% predicted within 1 year of follow-up Absolute decline in DLCO (Hb) > 10% predicted within 1 year of follow-up
3) Radiological progression (one or more of the following)	Increased extension or severity of traction bronchiectasis or bronchiolsoectasis New ground-glass opacity with traction bronchiectasis New fine reticulation Increased extent or increased coarseness of reticular abnormality New or increased honeycombing Increased lobar volume loss

Adapted from [8]

PFT pulmonary function test, FVC forced vital capacity, DLCO (Hb) diffusing capacity for carbon monoxide corrected for hemoglobin