Contemporary Fibrotic Interstitial Lung Disease Outcomes: A Multicentre National Cohort Study

BACKGROUND AND OBJECTIVE: This study determined contemporary transplant-free survival in fibrotic interstitial lung disease (ILD), identified baseline factors associated with death or transplant, and assessed performance of the ILD-GAP (Gender, Age, Physiology) index in a contemporary cohort. METHODS: Patients with idiopathic pulmonary fibrosis (IPF), fibrotic hypersensitivity pneumonitis (fHP), connective tissue disease-associated ILD (CTD-ILD), or unclassifiable ILD (uILD) prospectively enrolled in the Canadian Registry for Pulmonary Fibrosis were included. Transplant-free survival at 1, 3, and 5 years was estimated overall and by subtype using enrollment as time zero. Cox proportional hazards models evaluated associations between patient characteristics and time to death or transplant. ILD-GAP scores were calculated at 1, 2, and 3 years, and discriminability was assessed with Harrell's C statistic. RESULTS: Among 4236 patients with fibrotic ILD enrolled in the Canadian Registry for Pulmonary Fibrosis (CARE-PF), 31% had IPF, 40% CTD-ILD, 9% fHP, and 20% uILD. Overall transplant-free survival was 91% at 1 year, 72% at 3 years, and 57% at 5 years. Survival was lowest in IPF (87%, 61%, 39%) and highest in CTD-ILD (95%, 81%, 70%). Compared with IPF, CTD-ILD was associated with better 5-year survival after adjustment (hazard ratio 0.64 [0.55-0.76]). ILD-GAP showed moderate discrimination at 1 (C = 0.75), 2 (C = 0.74), and 3 years (C = 0.73). CONCLUSION: In this registry cohort anchored at enrollment, CTD-ILD had superior transplant-free survival versus IPF, and ILD-GAP provided moderate prognostic accuracy.