Acute exacerbation of progressive pulmonary fibrosis: incidence and outcomes.

Background: Few data are available on acute exacerbation (AE) in patients with progressive pulmonary fibrosis (PPF) besides idiopathic pulmonary fibrosis (IPF). This study aimed to investigate the AE incidence and outcomes among patients with PPF.

Methods: Clinical data of patients with PPF (n = 133) were retrospectively collected at a single center. PPF was defined based on the criteria used in the INBUILD trial. AE was defined as a worsening of dyspnea typically within 30 days with new bilateral lung infiltration and no evidence of cardiac failure or fluid overload.

Results: Among patients with PPF, the mean age was 60.6 years old, 57.1% were females, and the most common etiology was connective tissue disease-related ILDs (63%). During the follow-up (median: 38.0 months) after PPF diagnosis, 42 patients (31.6%) experienced AE. The 1-, 3-, and 5-year AE incidences were 12.5%, 30.3%, and 38.0%, respectively. Older age, rheumatoid arthritis associated ILD, fibrotic hypersensitivity pneumonitis, and lower lung diffusing capacity for carbon monoxide were AE risk factors. Patients with AE demonstrated worse survival (median survival: 30 months vs. not reached; p < 0.001) after PPF diagnosis than those without. AE was independently associated with mortality in patients with PPF (hazard ratio [HR], 2.194; 95% confidence interval [CI], 1.285-3.747; p = 0.004) in the multivariable Cox analysis, along with older age, lower lung diffusing capacity for carbon monoxide, and the usual interstitial pneumonia-like pattern on high-resolution computed tomography.

Conclusions: Our results suggest AE is not uncommon and significantly impacts on survival in patients with PPF.