Clinical Characteristics Of Combined Pulmonary Fibrosis And Emphysema Compared With Idiopathic Pulmonary Fibrosis

Background In the past,it was widely believed that pulmonary fibrosis and emphysema are two diseases in which the pathogenesis,progress and evolution are completely different and independent of each other.Pulmonary fibrosis [including Idiopathic pulmonary fibrosis(IPF)and idiopathic interstitial pneumonia] mainly affects the pulmonary interstitial and alveolar spaces,resulting in loss of alveolar-capillary function units,which clinical features are progressively exacerbated dyspnea,and pulmonary function tests show restrictive ventilatory dysfunction with reduced diffuse function,and imaging shows diffuse lung lesions with ground-glass,grid-like,and honeycomb changes.Emphysema is an early stage of Chronic obstructive pulmonary disease(COPD),which is an abnormal long-lasting dilatation of the distal bronchioles,accompanied by destruction of the alveolar wall and bronchioles without obvious pulmonary fibrosis.Chronic obstructive pulmonary disease can be diagnosed when there is persistent airflow limitation in the pulmonary function test of emphysema.With the deepening of research and the improvement of examination techniques,more and more people have noticed that emphysema and pulmonary fibrosis can occur simultaneously in the chest imaging of the same patient,which hasattracted the attention of many people.In 2005,V.cottin et al.based on the chest HRCT of 61 patients,retrospectively analyzed its clinical features and formally proposed the concept of disease of pulmonary fibrosis and emphysema(CPFE)syndrome.At present,many scholars at home and abroad have studied the CPFE syndrome and summarized its clinical features.IPF is a special type of chronic progressive fibrotic interstitial pneumonia of unknown cause,which histopathology and/or imaging findings are ordinary interstitial pneumonia(UIP).The clinical manifestations of CPFE syndrome are easily confused with IPF,and the differences in imaging findings,lung function characteristics,serological markers,and complications between the two are still unclear.Objective In this study,through the comparative analysis of general data,clinical features,pulmonary function,arterial blood gas analysis and HRCT in CPFE syndrome and IPF,the characteristics of CPFE syndrome were summarized and the clinical understanding of CPFE syndrome was deepened.Early detection,timely diagnosis,early treatment,and positive improvement of the disease and prognosis of patients with this disease,at the same time this study provides a reliable reference for the prospective study of the pathogenesis,diagnosis,treatment and prognosis of CPFE syndromeMethod Collect patient information through the case management system and retrieve patients with interstitial lung disease admitted to hospital from January 2013 to January 2018,according to the inclusion,exclusion criteria and the integrity of the medical history data,198 patients were enrolled.The patients were divided into CPFE group and IPF group according to the results of chest HRCT and pulmonary function tests,including 78 cases in CPFE group and 120 cases in IPF group.The general data such as gender,age,smoking history,and tumor markers,CRP,PCT and other serological indicators,arterial blood gas analysis indicators,lung function relatedindicators,chest HRCT and other findings were retrospectively collected.The measurement data analyzes the normality and the homogeneity of the variance,if the normal distribution and the homogeneity of the variance are satisfied,two independent sample t-tests are used,if the normal distribution is not satisfied,the Wilcoxon rank sum test is used,counting data using ?2 test.All data in the CPFE group were evaluated for normality and compared with DLCO.If the normal distribution is consistent,the regression coefficient uses the Pearson correlation coefficient to reflect the correlation.If it does not conform to the normal distribution,the rank correlation analysis using non-parametric test to test the correlation.The correlation coefficient was analyzed by Spearman rank correlation,P <0.05 was statistically significant.The Kaplan-Meier method was used to analyze the survival of the two groups,Log-Rank test was used to statistically test the difference of survival rate between the two groups,in which P<0.05 was considered statistically significant.Results 1.Both CPFE group and IPF group were more male than female.The smoking index of CPFE group was higher than that of IPF group,and the difference was statistically significant(t=4.744,P=0.002).2.Both CPFE group and the IPF group were mainly restricted by ventilatory dysfunction(40 cases in CPFE group and 66 cases in IPF group).The lung function related indexes of the two groups were compared: the mean values of TLC,FVC and FVC%pred,in the CPFE group were higher than in the IPF group,the mean values of FEV1,FEV1/FVC,DLCO,FEV1%pred and DLCO%pred in the CPFE group were all lower than those in the IPF group,the difference was statistically significant(P<0.05).3.Correlation analysis was performed between the indicators and DLCO in the CPFE group.The lung function indexes TLC,FVC,FEV1,FVC%pred,FEV1%pred and DLCO were correlated,and the composite physiological index and DLCO were also correlated(P<0.05).4.There were no significant differences in the scores of pulmonary fibrosis(t=-0.268,P=0.789)and grading(?~2=1.418,P=0.701)between the CPFE group and the IPF group.5.The survival time of the CPFE group was(34.54±20.574)months,and the survival time of the IPF group was(40.49±16.757)months.The survival time of the CPFE group was shorter than that of the IPF group.The difference was statistically significant(t=-2.230,P =0.027).The 1-,3-,and 5-year survival rates of the CPFE group were 85.9%,51.0%,and 26.8%,respectively.The 1-,3-,and 5-year survival rates of the IPF group were 96.7%,58.7%,and 32.3%,respectively.The survival rate of the two groups was analyzed by Kaplan-Meier,and the difference in survival rate between the two groups was statistically tested by Log-Rank test.The difference was statistically significant(?2=4.018,P=0.045).Conclusion 1.CPFE syndrome often occurs in elderly male patients,and smoking is the most common cause of CPFE syndrome.2.The typical lung function of CPFE syndrome is characterized by a significant decrease in diffuse function and is not proportional to airway obstruction and lung capacity.3.Emphysema and pulmonary fibrosis are not completely separate in lung HRCT manifestations of CPFE syndrome,and there are often both emphysema changes and pulmonary fibrosis changes in each lung field.