Level And Significance Of Biomarkers Related To Acute Exacerbation Of Chronic Obstructive Pulmonary Disease

Background:AECOPD（acute exacerbation of chronic obstructive pulmonary disease）exacerbations refers to exacerbation of chronic obstructive pulmonary disease,which is the most common cause of death in infectious diseases in developing countries,It is also an important cause of death and morbidity in developed countries^[1],and the incidence of chronic obstructive pulmonary disease（COPD）increases year by year.The main symptoms include cough,increased dyspnea,increased sputum volume or thickening,further deterioration of lung function,and reduced quality of life of patients.Although lung function examination is an important method to assess the severity of the disease,it has great limitations and is affected by many factors,such as elderly,severe or respiratory failure patients should not perform lung function examination,so more methods or indicators are needed for comprehensive evaluation.Relevant studies at home and abroad show that serum PCT（procalcitonin）,CRP（C-Reactive protein）and interleukin-6（interleukin-6）are objective and quantitative indicators,which can be quickly detected.Meanwhile,in recent years,studies have concluded that serum procalcitonin,C-reactive protein and interleukin-6 are related to the severity of COPD,and are reliable indicators to assess the severity and risk of death.Purpose:By collecting relevant data in healthy control group,patients with mild-moderate AECOPD and patients with severe AECOPD,the value of serum PCT,CRP and IL-6 in diagnosis,pulmonary function grading and severity of AECOPD was analyzed,providing evidence for timely diagnosis and treatment of patients with AECOPD.Method:The study subjects were selected from May 2019 to May 2022.All patients admitted to ICU of our hospital due to AECOPD were in need of ventilator assisted ventilation,and the selected number was 40（referred to as severe COPD group）.All patients admitted to the routine ward of respiratory department due to AECOPD did not need ventilator assisted ventilation,and 60 cases were selected（referred to as mild-moderate COPD group）.The selected subjects were 40 healthy persons without above diseases who underwent physical examination in the physical examination center of our hospital（referred to as the healthy control group）.The changes of serum PCT,CRP and IL-6 levels in the three groups were analyzed.Patients in severe COPD group were divided into death group and non-death group（according to death or not）,and the changes of serum PCT,CRP and IL-6 levels among the above groups were compared.Patients in mild to moderate COPD group were divided into grade 1 group（FEV₁%Pred≥80%）,grade 2 group（50%≤FEV₁%Pred<80%）,and Grade 3-4 group（FEV₁%Pred<50%）according to the lung function report.The changes of serum PCT,CRP,IL-6 levels and their relationship with lung function were compared among the three groups.Results:1.The serum PCT level of severe COPD group（0.48±0.08）μg/L was higher than that of mild-moderate COPD group（0.13±0.06）μg/L and healthy control group（0.06±0,04）μg/L,and the difference among the three groups was statistically significant（F=584.58,P<0.01）.The serum CRP level in the severe COPD group（47.04±7.98）mg/L was higher than that in the mild-moderate group（22.68±6.28）mg/L and the healthy control group（10.45±3.09）mg/L,and the difference among the three groups was statistically significant（F=293.24,P<0.01）.The serum IL-6 level in severe COPD group（18.83±7.49）pg/m L was higher than that in mild-moderate COPD group（11.26±6.83）pg/m L and healthy control group（5.79±2.86）pg/m L,and the difference among the three groups was statistically significant（F=44.83,P<0.01）.2.In the mild-moderate COPD group,the serum PCT level in grade 3-4 groups（0.18±0.04）μg/L was higher than that in grade 2 group（0.13±0.05）μg/L and grade 1group（0.08±0,04）μg/L,and the difference was statistically significant（F=19.00,P<0.01）.The serum CRP level in grade 3-4 groups（28.42±5.55）mg/L was higher than that in grade 2 group（22.64±5.14）mg/L and Grade 1 group（17.67±4.03）mg/L,and the difference was statistically significant（F=18.69,P<0.01）.The serum IL-6 level in grade 3-4 group（16.81±7.34）pg/m L was higher than that in grade 2 group（11.36±5.50）pg/m L and grade 1 group（6.20±4.20）pg/m L,and the difference was statistically significant（F=13.78,P<0.05）.3.In the severe COPD group,the serum PCT level in the death group（055±0.04）μg/L was significantly higher than that in the non-death group（0.46±0.07）μg/L,and the difference between the two groups was statistically significant（t=3.41,P<0.01）.The serum CRP level in death group（54.90±4.89）mg/L was significantly higher than that in non-death group（45.08±7.40）mg/L,and the difference between the two groups was statistically significant（t=3.54,P<0.01）.The serum IL-6level in the death group（26.15±5.59）pg/m L was significantly higher than that in the non-death group（17.00±6.79）pg/m L,and the difference between the two groups was statistically significant（t=3.51,P<0.01）.4.Serum PCT,CRP and IL-6 were negatively correlated with FEV₁%Pred（the percentage of FEV₁ in the predicted value）.5.The sensitivity of serum PCT,CRP,IL-6,and the combination of the three for the diagnosis of AECOPD were 70.6%,62.3%,72.0%,74.7%,and the specificity were92.5%,89.0%,87.5%,95.0%,respectively.Conclusion:Serum PCT,CRP,and IL-6 levels were elevated during acute COPD exacerbation,which contributed to the diagnosis of AECOPD,lung function（FEV₁%Pred）and severity assessment.