- RATIONALE: Real-life pharmacological treatment patterns of patients with interstitial lung diseases (ILD) remain elusive. OBJECTIVES: The objective of this study was to determine how often and with what medications patients with ILD are treated in Canadian tertiary care clinics. METHODS: All patients with ILD prospectively enrolled in the Canadian Registry for Pulmonary Fibrosis were included in this observational study. All first instances of medication for each patient were compiled. Time between the diagnosis of ILD and the first initiation of an ILD-related medication was compared across diagnostic categories. Cox proportional hazards models were used to identify variables associated with time-to-treatment initiation, stratified by diagnostic category. RESULTS: Out of 2,652 patients, a total of 1,483 (56%) were treated with an ILD-related medication during the median follow-up of 3.0 years (1.4 to 5.9), including 349/646 (54%) patients with idiopathic pulmonary fibrosis (IPF) who received an antifibrotic. Patients with IPF were treated earlier and in greater proportion compared to those with non-IPF ILD (p=0.001). Male sex and lower lung function were associated with shorter time to treatment initiation in the full cohort. CONCLUSIONS: Overall, 56% of patients with ILD seen across seven Canadian specialized ILD clinics received pharmacological treatment over a median follow-up of 3 years. Further studies are needed to assess longitudinal patterns of treatment and their influence on key outcomes.