Comparison of clinical characteristics and outcomes between combined pulmonary fibrosis and emphysema associated with usual interstitial pneumonia pattern and non-usual interstitial pneumonia.

BACKGROUND Recently, combined pulmonary fibrosis and emphysema (CPFE) has been recognized worldwide. However, actually CPFE had a variety of extent of emphysema or pulmonary fibrosis. OBJECTIVES The objectives of this study were to compare the clinical characteristics and outcomes between CPFE associated with usual interstitial pneumonia pattern (UIP) and CPFE with non-UIP divided based on chest high resolution computed tomography (HRCT) images, as well as to elucidate prognostic factors. METHODS A cohort of 57 CPFE and 64 IPF patients at a single institution was analyzed retrospectively. The HRCT imaging patterns of definite UIP pattern and possible UIP pattern were defined as UIP, and inconsistent with UIP pattern as non-UIP. Clinical characteristics and outcomes were compared in 3 subgroups with CPFE/UIP, CPFE/non-UIP, and IPF alone, respectively. The prognostic factors were performed using Cox proportional hazards. RESULTS The incidences of primary lung cancer and acute exacerbation (AE) were 10.4%/10.9% in CPFE/UIP, 0%/27.3% in CPFE/non-UIP, and 6.3%/35.9% in IPF, respectively. The survival in CPFE/UIP had significantly worse than that in other 2 subgroups (CPFE/non-UIP, IPF) (P = 0.011, P = 0.043). The multivariate Cox regression model showed that the prognostic factors of CPFE were UIP pattern and high-composite physiologic index (CPI). CPI thresholds of 45 provided the greatest prognostic separation in patients with CPFE. CPFE/UIP with high-CPI (CPI ≥ 45) had a worst prognosis compared with the other groups. CONCLUSIONS This study demonstrated that the presence of UIP pattern and high-CPI in CPFE patients were associated with poorer mortality.