Trajectory of lung function ‘varies considerably’ after ILD diagnosis

It is important to consider interstitial lung disease subtypes when applying progressive fibrosing ILD criteria, researchers concluded in an analysis published in European Respiratory Journal.

“Lung function trajectory varies considerably after ILD diagnosis and is influenced by several factors, including ILD diagnosis, [high-resolution CT] pattern and baseline FVC,” Justin M. Oldham, MD, the division of pulmonary, critical care and sleep medicine at the University of California, Davis, and colleagues wrote. “Near-term change in FVC after satisfying proposed [progressive fibrosing ILD] criteria is also heterogeneous depending on the criterion of interest and is strongly influenced by ILD diagnosis.”

Researchers conducted a retrospective, multicenter longitudinal cohort analysis that included 754 consecutive patients with fibrotic connective tissue disease-associated ILD, chronic hypersensitivity pneumonitis and idiopathic interstitial pneumonia from three U.S. centers (mean age, 61.7 years; 41.6% men) and 473 patients from one U.K. center (mean age, 58.7 years; 38.5% men). Researchers estimated change in FVC in 1 year after stratifying by proposed progressive fibrosing ILD.

Overall, 487 patients had connective tissue disease-associated ILD, 342 patients had chronic hypersensitivity pneumonitis and 398 had idiopathic interstitial pneumonia.

Two-thirds of progressive fibrosing ILD criteria were associated with a differential 1-year change in FVC. Radiological progression of fibrosis — both alone and in addition to other features — was associated with the largest subsequent FVC decline.

Researchers reported significant variation by ILD subtype. Connective tissue disease-associated ILD had little change in FVC (–37.2 mL) after satisfying most progressive fibrosing ILD criteria, the researchers wrote. Chronic hypersensitivity pneumonitis and idiopathic interstitial pneumonia were associated with larger changes in FVC (–92 mL and –69.5 mL, respectively).

Results did not vary after stratification by radiological pattern or immunosuppressant therapy exposure.

FVC near-term change after satisfying proposed progressive fibrosing ILD criteria was heterogenous dependent upon criterion assessed, the researchers wrote. This was also strongly influenced by the patients’ ILD subtype, according to the researchers.

“These findings may inform future clinical trial design and suggest ILD subtype should be taken into consideration when applying progressive fibrosing ILD criteria,” the researchers wrote.