The Correlation Between Peripheral Blood Eosinophils And NLR,FeNO And Lung Function In Patients With Acute Exacerbation Of Chronic Obstructive Pulmonary Disease

Objective:This study compared the clinical characteristics of patients with acute exacerbation of chronic obstructive pulmonary disease(AECOPD)at different levels of peripheral blood eosinophils(EOS).And to explore the correlation between blood EOS and neutrophil-to-lymphocyte ratio(NLR),fractional exhaled nitric oxide(FeNO)and lung function parameters.To analyze the risk factors of acute exacerbation of chronic obstructive pulmonary disease with increased eosinophils,and the predictive efficacy of NLR and FeNO on acute exacerbation of chronic obstructive pulmonary disease with increased EOS,so as to provide some reference for personalized treatment of patients with acute exacerbation of chronic obstructive pulmonary disease.Methods:Through the clinical electronic medical record system,126 patients with AECOPD who were hospitalized in the general ward of the Department of Respiratory and Critical Care Medicine of Shanxi Bethune Hospital from January 2021 to January 2022 were retrospectively collected.The patients were divided into low eosinophil group(EOS<2%,68 cases)and high eosinophil group(EOS≥2%,58 cases)according to the percentage of eosinophils in white blood cells(2%).The general clinical data(including age,gender,BMI,smoking index,comorbidities),hospitalization days,number of hospitalizations due to acute exacerbations in the past year,hormone use,hematological data within 24 hours of admission(including white blood cell count WBC,neutrophil count NEU,lymphocyte count LYM),lung function parameters(including forced vital capacity(FVC)before inhalation of bronchodilators,percentage of forced vital capacity to predicted value(FVC%),forced expiratory volume in one second(FEV1),percentage of forced expiratory volume in one second(FEV1%),the difference between the first second expiratory volume percentage of forced vital capacity(FEV1/FVC)and FeNO was calculated,and the ratio of neutrophil to lymphocyte count(NLR)was calculated.The correlation between peripheral blood EOS level and NLR,FeNO and lung function parameters was analyzed.Logistic regression analysis was used to explore the risk factors of patients with acute exacerbation of COPD with increased eosinophils,and receiver operating characteristic(ROC)was drawn to explore the predictive efficacy of NLR and FeNO in patients with acute exacerbation of COPD with increased eosinophils.Results:1.The hospitalization days of patients with acute exacerbation of COPD in the EOS≥2 % group were significantly lower than those in the EOS<2 % group.There were no significant differences in age,gender,BMI,smoking index,comorbidities,and number of hospitalizations due to acute exacerbations in the past year between the two groups.The number of days of intravenous hormone use and cumulative dose in EOS≥2% group were significantly lower than those in EOS<2% group.There was no significant difference in the number of days of inhaled hormone and cumulative dose.2.The WBC,NEU and NLR in the EOS≥2 % group were significantly lower than those in the EOS<2% group,and there was no significant difference in LYM between the two groups.3.The lung function parameters FVC and FEV1 in the EOS≥2% group were significantly higher than those in the EOS<2% group.There was no significant difference in FVC%,FEV1% and FEV1/FVC between the two groups.FeNO in EOS≥2% group was significantly higher than that in EOS<2% group.4.The level of blood EOS was negatively correlated with NLR,and positively correlated with FVC,FEV1 and FeNO.5.NLR and FeNO are risk factors for patients with acute exacerbation of chronic obstructive pulmonary disease with increased eosinophils.FeNO can effectively evaluate patients with acute exacerbation of chronic obstructive pulmonary disease with increased eosinophils.The optimal threshold for evaluation is 28.35 ppb,the sensitivity is 65.5%,and the specificity is 83.8%.NLR cannot effectively evaluate patients with acute exacerbation of chronic obstructive pulmonary disease with increased eosinophils.Conclusion:COPD patients with higher peripheral blood EOS levels have lighter airway inflammation and clinical symptoms during acute exacerbation.At the same time,the number of days and cumulative doses of intravenous hormones during hospitalization are less,and the number of days of hospitalization is less,suggesting that such patients have better responsiveness to systemic glucocorticoids and faster recovery of clinical symptoms.In addition,patients with higher EOS levels showed better lung function parameters.NLR and FeNO were risk factors for patients with acute exacerbation of chronic obstructive pulmonary disease with increased EOS.FeNO can be used as a biomarker to predict eosinophil airway inflammation in patients with acute exacerbation of chronic obstructive pulmonary disease.Good biomarkers are used to guide clinical treatment,but NLR cannot effectively evaluate patients with acute exacerbation of chronic obstructive pulmonary disease with increased eosinophils,and the diagnostic significance is small.This study is a single-center study with a small sample size,and the critical value of EOS is selected at a certain time point.However,due to the fluctuation of blood EOS value over time,it may be affected by other factors.At present,there is no uniform definition of the use of the critical value.Therefore,large sample,multi-center prospective study and further long-term follow-up are still needed to evaluate the predictive value of blood eosinophils in acute exacerbation of COPD patients,glucocorticoid use and prognosis.