The Correlation Between NLR And 5-year Mortality In AECOPD Patients

Objectives:The paper provides some scientific guides for clinical diagnosis,treatment and prevention of chronic obstructive pulmonary disease by studying the influencing factors of neutrophil/lymphocyte ratio(Neutrophil to lymphocyte ratio,NLR)in blood routine test(Blood routine test,BRT)in patients with acute exacerbation of chronic obstructive pulmonary disease(AECOPD)and the correlation between NLR and 5-year mortality in AECOPD patients.Methods:This is a retrospective cohort study.The research object is 114 patients with acute exacerbation of chronic obstructive pulmonary disease who were hospitalized in the Department of Respiratory Medicine of the second affiliated Hospital of Kunming Medical University from January 1st,2014 to October 31 st,2014.The end point of the study was all-cause death.The patients were followed up by consulting medical records and calling up.All patients were followed up death or 5 years(ending on October 31st,2019).Baseline general datas were collected through checking medical records such as sex,age,height,weight and smoking history;the laboratory indexes within 24 hours after being admitted to hospital,such as blood white blood cell count(WBC),neutrophil count(NC),lymphocyte count(LC),D-dimer(DD),C-reactive protein(CRP),liver enzyme,creatinine value and so on;respiratory failure,heart failure,pulmonary heart disease were recorded when the patient were hospitalized.The optimal cutoff value of NLR was determined according to the ROC analysis of NLR predicting all-cause death of AECOPD patients.The patients were divided into low NLR group(NLR<7.365)and high NLR group(NLR? 7.365)with 7.365 as the cut-off value.To compare the baseline general datas laboratory indexes,complications and clinical outcome;spearman correlation analysis was carried out between NLR and each index,and multiple linear stepwise regression model was used to analyze the influencing factors of NLR;Kaplan-Meier method was used to draw the survival curve.Log-rank method was used to compare the difference of survival rate between high NLR group and low NLR group;Univariate and multivariate Cox regression model was used to analyze the risk factors of all-cause death in AECOPD patients.That all datas were counted by SPSS 19.0 and P<0.05 was selected as the difference was statistically significant.Results:Among the 114 AECOPD patients,97 are male(85.1%),17 are female(14.9%),the average age is 71.47±9.34 years old,smokers(91 cases);cor pulmonale(91 cases),heart failure(40 cases)and respiratory failure(56 cases)accounted for 79.8%,35.1%and 49.6%respectively.The 5-year mortality rate of all patients is 42.1%,the overall survival time is 45.13(41.40-48.85)months.The best cut-off value of ROC curve analysis of NLR in predicting all-cause death of AECOPD patients is 7.365,and the area under the curve(AUC)is 0.662(0.562-0.761),the sensitivity is 43.80%,the specificity is 81.80%,and the Jordan index is 0.256.According to the NLR value of 7.365,all patients were divided into low NLR group(NLR<7.365,81 cases)and high NLR group(NLR?7.365,33 cases).The differences between the two groups in C-reactive protein,leukocyte count and neutrophil count(P<0.05)is statistically significant.Spearman correlation analysis shows that NLR is positively correlated with age(r=0.201),C-reactive protein(r=0.474),D-Dimer(r=0.246),leukocyte count(r=0.501),neutrophil count(r=0.646)(all P<0.05)is negatively correlated with lymphocyte count(r=-0.733),eosinophil count(r?-0.364),Serum albumin(r?-0.269,)and survival time(r=-0.246)(all P<0.05).The analysis of multiple linear stepwise regression model suggested that leukocyte count(B=0.906),C-reactive protein(B=0.373),D-Dimer(B=0.899)are independent factors of NLR(all P<0.05).Kaplan-Meier survival curve showed that the 5-year survival rate of patients of the low NLR group and the high NLR group is 66.7%to 36.4%,and the 5-year survival rate of patients of the low NLR group overtops the high NLR group(log-rank ?2=8.438,P=0.004).The Multivariate Cox regression analysis shows that NLR is an independent risk factor for all-cause death in AECOPD patients(HR=1.034,95%CI:1.007-1.061,P=0.014),and albumin is a protective factor for all-cause death in AECOPD patients(HR=0.868,95%CI:0.806-0.935,P<0.001).Conclusions:1.Leukocytes,C-reactive protein and D-Dimer are independent influencing factors of NLR in AECOPD patients.2.NLR is an independent risk factor for all-cause death in AECOPD patients.3.The best threshold for the NLR to predict the risk of death in AECOPD patients is 7.365.