Table 1.

Revised conceptual framework

	Subclinical SSc-ILD	Clinical SSc-ILD
Clinical features	All variables should be met but there may be exceptions	Must have ≥1 feature
Demographics	N/A	N/A
Age, sex, race
SSc disease factors	N/A	N/A
SSc cutaneous classification
Disease duration
ANA status
SSc specific autoantibody
Modified Rodnan Skin Score
Respiratory symptoms	None	Present
Mahler Dyspnoea Index and Transitional Index
Leicester Cough Questionnaire
Patient Global Assessment
St George’s Respiratory Questionnaire
Spirometry with gas exchange	Normal-to-near normal	Deficits present
Forced vital capacity (% predicted)
Diffusion capacity of carbon monoxide (% predicted)
Desaturation on exercise	Normal-to-near normal	Deficits present
Oxygen desaturation during 6-min walk test
Quantitative HRCT	Minimal-to-mild	Mild-to-severe disease
Whole lung involvement (% of ground glass opacities, fibrotic reticulations and honeycombing)
Whole lung fibrosis (% of only the fibrotic reticulations)
Disease impact	All features should be met	Must have ≥1 feature
Feel	None	Yes
Function	None	Yes
Survive	N/A	Yes
Disease progression	Must have ≥1 feature for either category (attributable to ILD)
Respiratory symptoms	New onset dyspnoea or cough	Advancing dyspnoea or cough
Spirometry with gas exchange	New decline	Advancing decline
Desaturation on exercise or exercise limitation	New desaturation and/or limitation	Advancing desaturation and/or limitation
Quantitative HRCT	New, larger extent of disease burden	Advancing extent of disease burden

CTD-ILD: CTD-interstitial lung disease; HRCT: high resolution CT; SSc-ILD: SSc associated interstitial lung disease.