It has been suggested that the presence of emphysema modifies the outcome of patients with idiopathic pulmonary fibrosis (IPF). In this article we compare clinical features, smoking history, pulmonary function, estimated systolic pulmonary artery pressure (eSPAP), and mortality in IPF with emphysema vs IPF without emphysematous changes.
A cohort of 110 IPF patients was evaluated. Clinical data were collected from clinical charts. High-resolution CT (HRCT) scans were examined by an expert blinded to clinical data, and patients were classified into the following two groups: patients with IPF with emphysema; and patients with IPF without emphysema. The Kaplan-Meier method, log-rank test, and Cox regression model were used for statistical analyses.
The prevalence of emphysema in the IPF cohort was 28% (31 of 110 patients). IPF with emphysema was significantly associated with male gender (odds ratio [OR], 18; 95% confidence interval [CI], 2.7 to 773.7; p = 0.0003), and smoking (OR, 3.8; 95% CI, 1.36 to 11.6; p = 0.004). Patients with IPF and emphysema had a higher mean (± SD) decrease in oxygen saturation during rest and exercise (16.3 ± 6.7% vs 13.5 ± 4.6%, respectively; p = 0.04), a higher mean fibrosis HRCT scan score (1.75 ± 0.36 vs 1.55 ± 0.38, respectively; p = 0.015), a higher eSPAP (82 ± 20 vs 57 ± 15 mm Hg, respectively; p < 0.0001), and lower median survival time (25 vs 34 months, respectively; p = 0.01) than patients with IPF without emphysema. The Cox regression model showed that the two most important variables associated with mortality were FVC < 50% predicted (hazard ratio [HR], 2.6; 95% CI, 1.19 to 5.68; p = 0.016) and eSPAP ≥ 75 mm Hg (HR, 2.25; 95% CI, 1.12 to 4.54; p = 0.022).
IPF patients with emphysema exhibited higher mortality compared with those with IPF without emphysema. This dire prognosis seems to be at least partially associated with the development of severe pulmonary arterial hypertension.