Visually stratified CT honeycombing as a survival predictor in combined pulmonary fibrosis and emphysema

Abstract

OBJECTIVE: To determine whether visually stratified CT findings and pulmonary function variables are helpful in predicting mortality in patients with combined pulmonary fibrosis and emphysema (CPFE). METHODS: We retrospectively identified 113 patients with CPFE who underwent high-resolution CT between January 2004 and December 2009. The extent of emphysema and fibrosis on CT was visually assessed using a 6- or 5-point scale, respectively. Univariate and multivariate Cox proportional regression analyses were performed to determine the prognostic value of visually stratified CT findings and pulmonary function variables in patients with CPFE. Differences in 5-year survival rates in patients with CPFE according to the extent of honeycombing were calculated using Kaplan-Meier analysis. RESULTS: An increase in the extent of visually stratified honeycombing on CT [hazard ratio (HR), 1.95; p = 0.018; 95% confidence interval (CI), 1.12-3.39] and reduced diffusing capacity of lung for carbon monoxide (DLCO) (HR, 0.97; p = 0.017; 95% CI, 0.94-0.99) were independently associated with increased mortality. In patients with CPFE, the 5-year survival rate was 78.5% for <5% honeycombing, 55.7% for 5-25% honeycombing, 32% for 26-50% honeycombing and 33.3% for >50% honeycombing on CT. CONCLUSION: The >50% honeycombing on CT and reduced DLCO are important prognostic factors in CPFE. ADVANCES IN KNOWLEDGE: Visual estimation of honeycombing extent on CT can help in the prediction of prognosis in CPFE.