Determination And Clinical Value Of Peripheral Blood Eosinophils In Chronic Obstructive Pulmonary Disease

Objective:To analyze the distribution of peripheral blood eosinophils(EOS)count in patients with Chronic Obstructive Pulmonary Disease(COPD)and its relationship with clinical characteristics,and explore the clinical application value in predicting the future risk of acute exacerbation(AE)and guiding the treatment of inhaled corticosteroids(ICS)to reduce the risk of AE.Method:This study is a single-center,prospective study,725 COPD patients were selected from The Second Xiangya Hospital of respiratory medicine clinics between January 2020 and December 2021.Demographic data,blood routine examination,AE in the past 1 year,exposure factors,lung function,m MRC and CAT score,drug treatments were collected.EOS was divided by 0.1×10~9/L and 0.3×10~9/L and patients were followed up for AE during 1 year.Results:The mean age of 725 patients was 65.9±8.8 years,and the median EOS was 0.14×10~9/L.The EOS of 225 patients(31.0%)was less than 0.1×10~9/L,346 patients(47.7%)had an EOS between 0.1-0.3×10?/L,and 154 patients(21.2%)had an EOS≥0.3×10~9/L.EOS≥0.3×10~9/L was positively correlated with body mass index≥24kg/m~2(a OR=1.58,a95%CI:1.06-2.34,P=0.03).The distribution of EOS was not correlated with the age,gender,frequency of AE and severity of AE,exposure types,GOLD grades,GOLD groups and severity of symptoms.Among 414 patients followed up,the incidence of AE,frequent AE,and severe AE at different levels of blood EOS showed no significant difference from that in the past year(P>0.05).ICS use was associated with a reduced risk of severe AE in the next year(RR=0.88,95%CI:0.79-0.97,P=0.01).In the blood EOS group between 0.1×10~9/L to 0.3×10~9/L,the improvement rate of severe AE was higher in ICS users than in non-ICS users(24.6%vs.7.3%,P=0.02).There was no difference in the improvement rates of AE,frequent AE,and severe AE between ICS users and non-ICS users in0.1×10~9/L and EOS≥0.3×10~9/L groups.Conclusion:The majority of patients with COPD have an EOS less than 0.3×10~9/L,and the EOS≥0.3×10~9/L is positively correlated with body mass index≥24kg/m~2.ICS reduced the risk of severe AE in COPD patients with blood EOS between 0.1×10~9/L to 0.3×10~9/L,while ICS showed no significant improvement in future AE in patients with EOS≥0.3×10~9/L.The patients of EOS≥0.3×10~9/L use ICS does not improve the risk of AE in the future.