One-Year Change in Quantitative Computed Tomography Is Associated with Meaningful Outcomes in Fibrotic Lung Disease

Whether change in fibrosis on high-resolution CT (HRCT) is associated with near- and longer-term outcomes in patients with fibrotic interstitial lung disease (fILD) remains unclear. We evaluated the association between 1-year change in quantitative fibrosis scores (DTA) and subsequent forced vital capacity (FVC) and survival in patients with fILD. The primary cohort included fILD patients evaluated from 2017-2020 with baseline and 1-year follow-up HRCT and FVC. Associations between DTA change and subsequent FVC were assessed using linear mixed models. Transplant-free survival was assessed using Cox proportional hazards models. The Pulmonary Fibrosis Foundation (PFF-PR) Patient Registry served as the validation cohort. The primary cohort included 407 patients (median [IQR] age, 70.5 [64.8, 75.9] years; 214 male). One-year increase in DTA was associated with subsequent FVC decline and transplant-free survival. The largest effect on FVC was observed in patients with low baseline DTA scores in whom a 5% increase in DTA over 1 year was associated with a change in FVC of -91 mL/year [95% CI: -117, -65] (vs stable DTA: -49 mL/year [95% CI: -69, -29]; p=0.0002). The hazard ratio for transplant-free survival for a 5% increase in DTA over one year was 1.45 [95% CI: 1.25, 1.68]. Findings were confirmed in the validation cohort. One-year change in DTA score is associated with future disease trajectory and transplant-free survival in patients with fILD. DTA could be a useful trial endpoint, cohort enrichment tool, and metric to incorporate into clinical care.