Study design: A prospective cohort study with a longitudinal design, with several parameters measured serially at baseline and at pre-specified time points during three to five years of clinical observation.

Primary objective: To validate quantitative analysis of lung sounds as a marker of disease progression in a cohort of patients with Interstitial Lung Disease (ILD) via correlation with the extent of fibrosis on HRCT, measured both via visual scoring and quantitative CT assessment, and other validated parameters of disease progression such as FVC, tolerance to exercise and patient-related outcomes (symptoms and quality of life).

Secondary objectives: To determine the prognostic value of quantitative analysis of lung sounds and a series of novel putative biological markers, obtained from peripheral blood and bronchoalveolar lavage, toward poor outcomes (death, categorical decline of % predicted FVC >10%, acute exacerbation or respiratory-related hospitalisations) as compared to more conventional clinical, physiology and radiologic measurements.

Inclusion Criteria:

• diagnosis of ILD, made according to international guidelines where available
• age between 40 and 90 years

Exclusion Criteria:

• significant comorbidities or physical impairment that could affect participation

Consecutive patients with a diagnosis of ILD