Serum surfactant protein D (SP-D) and annual decline of diffusion capacity are prognostic factors for combined pulmonary fibrosis with emphysema (CPFE) in idiopathic pulmonary fibrosis (IPF)

Abstract

Background

The disease concept, CPFE is proposed recently. It is rare that clinical course of CPFE and relationship between serum markers and survival are reported. We conducted a retrospective clinical study of CPFE in patients of IPF.

Methods

A hundred and seven patients with interstitial pneumonia who visited Sapporo Medical University Hospital and Teine Keijinkai Hospital from 2007 to 2012 were investigated retrospectively. Seventy-two patients were diagnosed as IPF according to the ATS/ERS statement and were enrolled in this study. The patients were diagnosed as CPFE who were scored more than two points according to Goddard classification by HRCT. Thirty-four patients were CPFE and 38 were “non-CPFE”. Their medical records including pulmonary function test and serum markers (SP-A, SP-D, KL-6) were reviewed.

Results

In CPFE patients, lung capacity was kept and diffusion capacity was decreased as same as past reports. CPFE patients showed significantly worse survival than non-CPFE (p=0.0059). Worsening of diffusion capacity and high level of serum SP-D at the initial status showed poor prognosis. There was a significant difference in serum SP-D between CPFE and non-CPFE. Moreover, in CPFE patients, higher serum SP-D group (more than 150 ng/ml) showed significantly worse survival than another group (p=0.0089).

Conclusion

In IPF, CPFE patients showed significantly worse survival than non-CPFE, and CPFE patients with high serum SP-D showed poor prognosis. It is suggested IPF patients with emphysema on HRCT and high SP-D level in sera should be needed careful observation.