Significance Of Peripheral Blood Eosinophil Stratification In Acute Exacerbation Of Chronic Obstructive Pulmonary Disease

Background:Chronic obstructive pulmonary disease（COPD）is a common chronic respiratory disease,which seriously affects people’s health and quality of life,and its morbidity and mortality are increasing year by year.Acute exacerbation of chronic obstructive pulmonary disease（AECOPD）is usually accompanied by increased airway inflammatory indicators,such as high-sensitive C-reactive protein（hs-CRP）,serum amyloid A（SAA）,and the role of eosinophil（EOS）in this process still needs to be further explored.Objective:To investigate the relationship between peripheral blood eosinophil stratification and inflammatory markers,lung function and risk of readmission in patients with acute exacerbation of COPD,and to clarify the role of eosinophil in acute exacerbation of COPD.Methods:A total of 106 patients with acute exacerbation of COPD admitted to the Department of Respiratory Medicine of the Second Affiliated Hospital of Dalian Medical University from January 2019 to May 2020 were collected as the research subjects,including 89 males and 17 females.According to the percentage of eosinophils in peripheral blood detected in the blood routine for the first time on admission,the patients were divided into two groups using 2%eosinophils percentage as the threshold:group with eosinophils percentage<2%,a total of 55 patients with an average age of（70.75±9.75）years;There were 51 patients in the eosinophil percentage≥2%group,with an average age of（70.29±8.92）years;General patient information was recorded including gender,age,and smoking index.Detection of peripheral blood serum amyloid A（SAA）,high-sensitive C-reactive protein（hs-CRP）,procalcitonin（PCT）and white blood cell count（WBC）,neutrophil percentage（NEUT%）and pulmonary function index（FEV₁/FVC%）of A second rate,percentage of forced expiratory volume in the first seconds of expected value（FEV₁%pre）,and half an year internal cause acute aggravating readmission in patients with follow-up.Measurement data were expressed as mean±standard deviation（（?）±s）,and t test was used for comparison between the two groups.Enumeration data are presented as percentages（%）,and comparison is performed using the x² test.P<0.05was considered statistically significant.Result:1.A total of 106 patients with acute exacerbation of COPD were collected,including 55 males/females（45/10）in the EOS<2%group.There were 51 patients（male/female（44/7））in EOS≥2%group.The mean age of the EOS<2%group was（70.75±9.75）years old,and the mean age of the EOS≥2%group was（70.29±8.92）years old.There was no significant difference in gender and age between the twogroups（P>0.05）.The smoking index of EOS<2%group was（29.55±31.85）bale year,and that of EOS≥2%group was（33.34±27.45）bale year,with no statisticalsignificance（P>0.05）.2.FEV₁%pre of EOS<2%group and EOS≥2%group were（55.32±18.86）%and（54.58±18.66）%,respectively,and there was no significant difference between the two groups（P>0.05）.FEV₁/FVC%in EOS<2%group and EOS≥2%group were（60.82±10.50）%and（60.49±13.85）%,respectively,and there was no statistical significance（P>0.05）.3.According to EOS stratification,the readmission rate due to acute exacerbation was compared between the two groups.In the EOS<2%group,8 cases were readmission within half a year,and the readmission rate was 15%.The readmission rate of 17 patients in the EOS≥2%group was 33%,and the readmission rate in the EOS≥2%group was significantly higher than that in the EOS<2%group,the difference was statistically significant（x²=0.023,P<0.05）.4.The levels of SAA in EOS<2%group and EOS≥2%group were（121.33±123.37）mg/L and（44.18±88.95）mg/L,respectively.EOS<2%group was significantly higher than that of EOS≥2%group（P<0.05）.The hs-CRP levels in the above two groups were divided into（39.42±55.06）mg/L and（11.83±26.52）mg/L.The EOS<2%group was higher than the EOS≥2%group,and the difference was statistically significant（P<0.05）.PCT levels in EOS<2%group and EOS≥2%group were divided into（0.11±0.32）ng/m L and（0.05±0.10）ng/m L,The EOS<2%group was higher than the EOS≥2%group,and the difference was statistically significant（P<0.05）.WBC level was divided into（7.75±2.64）×10⁹/L and（6.22±1.57）×10⁹/L.The levels of NEUT%were（74.32±10.74）%and（61.31±7.98）%.The above inflammatory indexes in EOS<2%group were higher than those in EOS≥2%group,and the difference was statistically significant（P<0.05）.Correlation analysis showed that the percentage of EOS and negatively correlated to the levels of SAA（r=0.426,P=0.000）,and negatively correlated with the hs-CRP levels（r=0.375,P=0.000）,the percentage of EOS and negatively correlated with the PCT level（r=0.337,P=0.001）,EOS percentage and negatively correlated to the level of WBC（r=0.286,P=0.003）,the percentage of EOS and negatively correlated with NEUT%level（r=0.681,P=0.001）.Conclusions:The levels of eosinophils were negatively correlated with inflammatory markers hs-CRP,SAA,PCT,WBC and NEUT%in patients with acute exacerbation of COPD.Patients with hyper eosinophilic COPD have a higher rate of readmission due to acute exacerbation,maybe a potential marker for predicting the risk of acute exacerbation.