Coexistent emphysema delays the decrease of vital capacity in idiopathic pulmonary fibrosis

Abstract

Although previous authors have reported single data point, yearly changes in respiratory function have not been examined in combined pulmonary fibrosis and emphysema (CPFE). To quantify the annual changes in respiratory function of patients with CPFE and to examine the difference in survival between CPFE patients and patients with idiopathic pulmonary fibrosis without emphysema (IPF alone), 26 patients with CPFE and 33 IPF alone patients, whose respiratory function had been monitored for at least a year, were selected. The baseline of vital capacity percent predicted (VC% pred) in CPFE patients was greater than that in IPF-alone patients (86.6+/-24.0% vs. 72.8+/-19.4%, p=0.018). The annual decrease in VC% pred was significantly less in CPFE patients than in IPF-alone patients (-1.2+/-4.8% vs. -8.0+/-7.4%, p<0.001). Baseline ratio of forced expiratory volume in one second to forced vital capacity (FEV(1)/FVC%) in CPFE patients was lower than that in IPF-alone patients (76.6+/-8.5% vs. 85.2+/-6.7%, p<0.001). In the CPFE group, FEV(1)/FVC% tended to decrease with time (-0.5+/-2.2% per year), but, in contrast, it increased in IPF-alone patients (+1.1+/-3.4% per year) (p=0.036). Baseline of diffusing capacity percent predicted (DLco% pred) was significantly lower in CPFE patients than in IPF-alone patients (45.3+/-15.0% vs. 60.7+/-19.8%, p=0.003). The annual decrease in DLco% pred was lower in CPFE patients than in IPF-alone patients (-3.7+/-7.9% vs. -10.7+/-8.8%, p=0.042). There was no significant difference in the survival duration between 26 CPFE and 33 IPF-alone patients according to Kaplan-Meier analysis. Ventilatory and gas-exchange deterioration during the course of IPF became mild when emphysema was coexistent.

The impact of emphysema in pulmonary fibrosis

“…The quantification and interpretation of disease severity using pulmonary function tests in patients with IPF is often confounded by coexistent emphysema and results in a spurious preservation of lung volume and depression of gas transfer [30,31]. However, although pulmonary function tests usually show respiratory volumes and flows that are normal or subnormal, diffusing capacity of the lung for carbon monoxide (DLCO) is substantially reduced and exercise hypoxaemia is common (table 2).…”

Significance of Combined Emphysema in Idiopathic Pulmonary Fibrosis and Serum Surfactant Protein-D as a Prognostic Factor

“…8,9,[28][29][30][31] There seem to be two explanations for this: differences in the assessment of emphysema area on HRCT and race differences. Standardization of diagnosis criteria and a large-scale study that takes race into consideration are areas for future research.…”

Combined Pulmonary Fibrosis and Emphysema Syndrome in a Patient Age 28 Years with Severe Systemic Sclerosis: Figure 1.

“…Mean age at diagnosis was between 65 and 70 years in the largest series of "idiopathic" CPFE 1,3,4,5,6 , and no patient was previously diagnosed before the age of 36 years 1 .…”

“…This syndrome is mainly related to heavy tobacco smoking, with about 95% of smokers and a mean of ~40 pack-years in CPFE patients without CTD 1,3,4,5,6 . CPFE has been reported recently in patients with CTD, especially rheumatoid arthritis and SSc 2 .…”