Correlation Of Fat Free Mass Index With Clinical Features And Serum Inflammatory Factors In Male COPD Patients

Objective: This study used fat free mass index to evaluate the nutritional status in patients with COPD,and detect the incidence of malnutrition.We analyzed the relationship between symptoms,lung function,exercise endurance and nutritional status.At the same time,the levels of TNF-α and IL-18 in serum were detected,and their correlations with nutritional indexes were analyzed.We investigated the level of systemic inflammatory response under different nutritional status in stable COPD and explored the mechanism of malnutrition.Methods: Eighty-six patients with stable COPD and 51 healthy subjects were enrolled.The personal data(age,sex,height,weight,smoking history,etc.)and basic clinical data(symptom,course of disease and the risk of acute exacerbation in the past year,etc.)were collected.CAT score,6 minute walk distance,lung function test and body composition were performed.Each subject was drawn peripheral venous blood 10 ml for the detection of serum TNF-α、IL-18 concentrations.SPSS 23.0 statistical software was for statistical analysis.Statistical analysis of the normal distribution of data between groups was used independent sample t-test analysis,with noncompliance used rank sum test(Mann-Whitney test).The correlation between the two variables was analyzed using Pearson correlation or Spearman correlation analysis.Multivariate linear regression was used to analyze the association of the relevant factors with FFMI.Results: 1、The serum TNF-α and IL-18 levels in stable COPD patients were significantly higher than those in normal controls(P <0.05),while the BMI,FFMI,FMI,6 minute walking distance and lung function index(FVC% predicted,FEV1% predicted,FEV1 / FVC)were significantly lower than those in the normal control group(P <0.05).2、The incidence of malnutrition in stable COPD group was significantly higher than that in normal control group(c2= 23.837,P <0.05).The levels of serum TNF-α and IL-18 in stable COPD group were significantly higher than those in normal control group(P <0.05).3、The patients with stable COPD were divided into low FFMI group(n = 44)and normal FFMI group(n = 42).Clinical data,body weight,BMI,mMRC scores,FEV1% predicted,FEV1 / FVC,and six-minute walking distance between the two groups were significantly different,while the difference was statistically significant(P <0.05).The levels of serum TNF-α and IL-18 in low FFMI group were significantly higher than those in normal FFMI group,with significant difference between the two groups(P <0.05).4、There was a positive correlation between FFMI and six-minute walking distance,FEV1% predicted,and FEV1 / FVC in patients with stable COPD(r = 0.226-0.416,P <0.05).However,the number of acute exacerbations,mMRC score,serum TNF-α and serum IL-18 levels in the previous year were negatively correlated with FFMI(r =-0.437-0.506,P <0.05).There is a strong negative correlation between serum TNF-α and FFMI.5、Using stepwise multiple linear regression analysis,6MWT,serum TNF-α level and serum IL-18 level were the independent influential factors of FFMI(b = 0.008,-0.240,-0.004,P <0.05).Conclusions: 1、Compared with the normal control group of the same age,the incidence of malnutrition in stable COPD patients is high.2、Stable COPD patients with malnutrition had more severe respiratory distress,higher risk of exacerbations,poorer pulmonary function and exercise tolerance.3、Serum TNF-α and IL-18 were highly expressed in stable COPD patients with low FFMI,which may be involved in the pathogenesis of COPD malnutrition.4、Serum TNF-α in COPD patients was closely related to FFMI,and was an independent predictor of malnutrition.