RT Journal Article SR Electronic T1 The decline in lung function is related to both emphysema and fibrosis extent in patients with idiopathic pulmonary fibrosis (IPF)/ combined pulmonary fibrosis and emphysema (CPFE) JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP P747 VO 44 IS Suppl 58 A1 Vincent Cottin A1 David Hansell A1 Katerina Antoniou A1 Arjun Nair A1 Mark Atwood A1 Nicola Sverzellati A1 Gerry Oster A1 Derek Weycker A1 Harold R. Collard A1 Athol Wells YR 2014 UL http://erj.ersjournals.com/content/44/Suppl_58/P747.abstract AB Background: Concurrent emphysema may be associated with spurious preservation of FVC in CPFE. Serial FVC measurement used to monitor progression in IPF might fail to capture disease progression in CPFE.Aim: To evaluate the change in FVC% predicted over time in patients with IPF and CPFE in relation to the extent of emphysema and fibrosis on HRCT.Methods: The extent of fibrosis and emphysema on baseline HRCT scans was quantified by visual estimation in 309 patients participating in a placebo-controlled clinical trial of interferon γ-1b with evaluable HRCT scans. The diagnosis of IPF was made using ATS/ERS 2000 criteria, with surgical lung biopsy in 58.3% of patients.Results: The mean age was 66.0±8.1 years, including 225 males (72.8%) with 68.0% former and 5.2% current smokers. At baseline, FVC% predicted was 73.2±13.5% and DLco was 46.9±8.6%. Emphysema was present in 121 patients (39%). The extent of emphysema was negatively related with the extent of fibrosis (r = -0.277, p < 0.001 ; and test of linear trend, p=0.01). The 48-week decrease in FVC% predicted was correlated with the extent of fibrosis (r = 0.249; p < 0.001), and inversely correlated with the extent of emphysema (r= -0.115; p=0.044). Patients with less fibrosing disease and those with a higher extent of emphysema showed less decline of FVC% predicted, but no less decline in DLco and no greater increase in CPI score.Conclusions: In patients with IPF and associated emphysema (CPFE), change in FVC may not be a sensitive measure of disease progression. These findings have implications for both patient management and clinical trial design.