Study On The Correlation Between Peripheral Blood Eosinophil And Acute Exacerbation Risk And Mortality Rate In Patients With Chronic Obstructive Pulmonary Disease Within One Year

Objective: To investigate the relationship between peripheral blood eosinophil(EOS)level and risk of acute exacerbation within 1 year,mortality within 1 year,failure rate of early treatment,length of hospital stay and other related index,using data collected from patients with AECOPD(acute exacerbation of chronic obstructive pulmonary disease).Methods: The clinical data of 349 patients with AECOPD hospitalized in the Department of Respiratory Medicine,the first affiliated Hospital of Medical College of Shihezi University from October 2015 to October 2017 were analyzed retrospectively.In addition,350 healthy volunteers were surveyed as the control group.To analyze the difference of peripheral blood eosinophil levels among AECOPD group,stable phase group and control group.The patients were divided into two groups according to their percentage of eosinophils in peripheral blood being either above 2% or below 2% at admission.The differences of white blood cell(WBC),C-reactive protein(CRP),procalcitonin(PCT),neutrophil/lymphocyte ratio(NLR),early treatment failure rate,hospitalization days,times of acute exacerbation in 1 year and mortality in 1 year between the two groups were compared.Logistic regression analysis was applied to analyze the effect of eosinophil percentage and count on frequent acute exacerbation,and the best cut-off point for predicting acute exacerbation was selected according to the ROC curve.Analysis of the correlation between peripheral blood eosinophil and exhaled nitric oxide(FeNO)was conducted using Pearson correlation.Results: The percentage and count of peripheral blood eosinophils in AECOPD group were higher than those in stable stage group and healthy control group(P <0.05).Patients with eosinophil ≥2% in peripheral blood had lower WBC,CRP,PCT and NLR,lower failure rate of early treatment,shorter hospitalization days and more times of acute exacerbation within one year than those with eosinophil <2%(P <0.05).But there was no difference in mortality between the two groups within one year(P≥0.685).With the increase of peripheral blood eosinophil count and percentage,the risk of frequent acute exacerbation increased in the future(P < 0.05),and the predictive value of peripheral blood eosinophil count for acute exacerbation was better than that of percentage.The best cut-off point for predicting the risk of future acute exacerbation of peripheral blood eosinophil count was 180 cells/ul(sensitivity 61%,specificity 80%).The percentage and count of eosinophils in peripheral blood were positively correlated with FeNO(r = 0.653,0.588,P < 0.05).Conclusion: 1.Peripheral blood eosinophil level is a good predictor of the risk of frequent acute exacerbation in AECOPD patients in the next year,but malfunctions when identifying the risk of death.2.The level of eosinophil in peripheral blood can be used to evaluate the failure rate of early treatment,the length of stay in hospital and bacterial infection of patients with AECOPD.3.The level of eosinophil in peripheral blood was consistent with that of FeNO in the evaluation of eosinophilic airway inflammation in patients with AECOPD.