Prognostic impact of emphysema extent on mortality and lung function decline in combined pulmonary fibrosis and emphysema: An observational cohort study

BACKGROUND: Combined pulmonary fibrosis and emphysema (CPFE) is a well-recognized syndrome characterized by the coexistence of emphysema and fibrotic interstitial lung disease (ILD) and is associated with high mortality. However, the prognostic significance of emphysema extent relative to fibrosis pattern remains incompletely defined. METHODS: We conducted an observational cohort study of participants with fibrotic ILD and radiographic emphysema. Baseline high-resolution computed tomography (HRCT) scans were independently assessed by two thoracic radiologists using a standardized semi-quantitative scoring system. Cox proportional hazards regression was used to evaluate associations between imaging features and all-cause mortality. RESULTS: Ninety-two participants with CPFE were followed for a median of 8 years, during which 70% died. Cumulative mortality was 4.4% at 1 year, 21.7% at 3 years, and 30.5% at 5 years. Most participants demonstrated a definite usual interstitial pneumonia pattern and centrilobular emphysema, with the majority having 5% emphysema had a significantly higher risk of death (HR 3.96, 95% CI 1.43-10.95; p = 0.008). Fibrosis pattern, emphysema subtype, and regional disease distribution were not independently associated with mortality. CONCLUSION: Semi-quantitative emphysema extent on HRCT is a strong, independent prognostic marker in CPFE. These findings support routine assessment of emphysema burden to inform risk stratification in CPFE.