Clinical Significance Of Neutrophil/Lymphocyte Ratio In Chronic Obstructive Pulmonary Disease

Objective:To detect the changes of peripheral blood neutrophil/lymphocyte ratio（NLR）and hypersensitive C-reactive protein（hs-CRP）in patients with acute exacerbation of chronic obstructive pulmonary disease（AECOPD）.To compare and analyze the correlation between NLR and white blood cell count（WBC）,hs-CRP,procalcitonin（PCT）and pulmonary function,to explore the value of NLR in the diagnosis of AECOPD and its evaluation,and to provide reference indicators for the evaluation of patients with AECOPD.Methods:A total of 118 patients with AECOPD and 26 patients with stable COPD（SCOPD）in the second affiliated Hospitial of Dalian Medical University from January 2017 to January 2020 were collected,and 33 healthy persons were selected for physical examination in the same period.All subjects improved chest CT,pulmonary function test,blood routine test,hypersensitive C-reactive protein and procalcitonin test.Record general and clinical data.General data include:age,sex,height,weight and body mass index（BMI）.The hospitalization days of AECOPD patients were recorded.The clinical data included white blood cell count（WBC）,neutrophil count（N）,lymphocyte count（L）,percentage of neutrophil（N%）,percentage of lymphocyte（L%）,percentage of eosinophil（EOS%）,procalcitonin（PCT）,hs-CRP,pulmonary function indexes（FEV₁,FEV₁%pred,FVC,FVC%pred,FEV₁/FVC）and calculate the NLR=N/L.To explore the differences of NLR,hs-CRP,WBC,L%and N%among healthy control group,SCOPD group and AECOPD group.To explore the correlation between NLR,PCT,hs-CRP,WBC,EOS%and pulmonary function indexes in SCOPD group and AECOPD group.According to PCT with 0.06ng/ml as the critical value,AECOPD group was divided into PCT normal group（PCT≤0.06 ng/m L）and PCT elevation group（PCT>0.06ng/m L）.Taking AECOPD as the state variable,the ROC curve was made to evaluate the value of NLR,hs-CRP and NLR combined with hs-CRP in the diagnosis of AECOPD,and the area under the curve,sensitivity,specificity,95%confidence interval（95%CI）and cutoff value were recorded.All data were analyzed by SPSS 25.0 statistical software.Results:1.This study included 33 healthy controls,including 22 males and 11females,with an average age of 66.48±7.65（years）.There were 26 patients in SCOPD group,including 21 males and 5 females,with an average age of 68.08±10.65（years）.There were 118 patients in AECOPD group,including 93 males and 25 females,with an average age of 68.03±8.94（years）.There was no significant difference in age and sex among the three groups（P>0.05）.2.Compared with healthy control group and SCOPD group,hs-CRP,N%and NLR in AECOPD group increased,hs-CRP:0.97（0.17-3.44）mg/L vs 1.37（0.76-3.48）mg/L vs 7.51（1.62-32.51）mg/L,N%:59.10（51.35-65.75）%vs 63.90（56.93-67.43）%vs 66.55（61.80-75.03）%,NLR:1.90（1.37-2.54）vs 2.21（1.66-3.07）vs 3.06（2.33-4.73）,the difference was statistically significant（P<0.05）;L%in AECOPD group decreased significantly（32.13±7.61%vs 28.44±8.06%vs 20.94±7.64%）,the difference was statistically significant（P<0.05）.Compared with the healthy control group,the WBC of AECOPD group was significantly higher（5.90（5.10-6.64）×10⁹/L vs 7.54（6.01-9.14）×10⁹/L）,and the difference was statistically significant（P<0.05）.Compared with the healthy control group,there was no significant difference in the above-mentioned indexes between the SCOPD group and the healthy control group（P>0.05）.3.In SCOPD group,NLR was positively correlated with WBC（r=0.601,P=0.001）,but not with PCT,hs-CRP and EOS%（P>0.05）.In AECOPD group,NLR was positively correlated with PCT,hs-CRP and WBC（r=0.266,P=0.004,r=0.237,P=0.010,r=0.488,P<0.001）,and negatively correlated with EOS%（r=-0.422,P<0.001）.4.In SCOPD group,NLR was negatively correlated with FEV₁and FEV₁%pred（r=-0.467,P=0.016,r=-0.407,P=0.039）,but not with FVC,FVC%pred and FEV₁/FVC.In AECOPD group,NLR was negatively correlated with FEV₁%pred and FVC%pred（r=-0.210,P=0.023;r=-0.249,P=0.007）,but not with FEV₁,FVC and FEV₁/FVC（P>0.05）.5.In AECOPD group,compared with the normal PCT group,there was no significant difference in hospitalization days,age,sex,BMI and WBC in the PCT elevated group（P>0.05）,NLR,hs-CRP level increased,NLR:2.85（2.28-4.29）vs 4.50（2.75-12.61）,hs-CRP:5.94（1.29-14.17）mg/L vs 53.86（24.41-135.55）mg/L,and the difference was statistically significant（P<0.05）.6.Taking AECOPD as the state variable,the ROC curve was made to evaluate the value of NLR,hs-CRP and NLR combined with hs-CRP in the dia-gnosis of AECOPD.It is concluded that the area under the AECOPD curve of NLR diagnosis is 0.734（95%CI:0.629-0.840）,the cutoff value is 2.0314,the sensitivity is 89.8%,and the specificity is 46.2%,P<0.001.For hs-CRP diagnosis,the area under the AECOPD curve is 0.731（95%CI:0.645-0.817）,the cutoff value is 8.11mg/L,the sensitivity is 49.2%,and the specificity is96.2%,P<0.001.The area under the AECOPD curve diagnosed by NLR combined with hs-CRP was 0.812,the sensitivity was 61.0%,and the specificity was 84.6%,P<0.001.Conclusion:NLR has a certain value in the diagnosis of acute exacerbation of chronic obstructive pulmonary disease,and the diagnostic value of NLR combined with hs-CRP is better.There is a certain correlation between NLR and pulmonary function and inflammatory index in patients with acute exacerbation of chronic obstructive pulmonary disease.