Table 2.

Suggested criteria or definitions of progressive fibrosis in clinical practice.

Suggested inclusion criteria 1 for clinical practice	Ref.
Patients meeting any of the following criteria within a 24-month period may have PF-ILD: •Relative decline of ≥10% in FVC •Relative decline of ≥15% in DLCO •Worsening symptoms or worsening HRCT signs accompanied by a relative decline of FVC ≥5-<10% (HRCT signs must be assessed by experienced thoracic radiologist)	[11]
Suggested inclusion criteria 2 for clinical practice	Ref.
Patients excluded the alternative explanations such as respiratory tract infection and meeting any of the following criteria can be considered to have PF-ILD: •Relative decline of 10% or more in FVC over 24 months despite treatment •Relative decline in FVC of 5% or more with decline in DLCO of 15% or more over 24 months despite treatment •Relative decline in FVC of 5% or more with increased fibrosis on HRCT over 24 months despite treatment •Relative decline in FVC of 5% or more with progressive symptoms over 24 months despite treatment •Progressive symptoms with increased fibrosis on HRCT over 24 months despite treatment (HRCT signs must be assessed by experienced thoracic radiologist)	[19]

CPI: Composite Physiologic Index; DLCO: diffusing capacity of the lung for carbon monoxide; FVC: forced vital capacity; HRCT: high-resolution CT; PF-ILD: progressive-fibrosing interstitial lung disease.