The Diagnostic Value Of Serum 25(OH)D Level In Acute Exacerbation Of Chronic Obstructive Pulmonary Disease

Objective To assess the serum 25（OH）D level in patients with AECOPD,and compare it with PCT,CRP,IL-6 inflammatory biomarkers to explore the diagnostic value of serum 25（OH）D for AECOPD.Subject and methods Based on inclusion and exclusion criteria,76 patients with AECOPD seen in the Department of Respiratory and Critical Care Medicine from October 2018 to June 2020 were prospectively included（AECOPD group）,and 70patients with stable COPD（SCOPD group）and 54 healthy controls（CON group）were selected.General clinical data such as age,sex,height,weight,smoking history and duration of illness were collected from all enrolled participants,serum 25（OH）D,CRP,PCT and IL-6 levels were measured in the AECOPD,SCOPD and healthy control groups and pulmonary function measurements were completed,and the lung function parameters such as FEV₁,FEV₁/FVC,FEV₁%pred were measured and recorded.To compare the differences in serum 25（OH）D,PCT,CRP,IL-6 and lung function indexes among the three groups,the patients in the AECOPD group were classified according to the Global Initiative for COPD（GOLD）lung function severity grading standard,and analyzed the correlation between serum 25（OH）D and serum PCT,CRP,IL-6 levels and pulmonary function indicators FEV₁,FEV₁/FVC,FEV₁%pred and GOLD classification,and ROC curves were plotted to analyze the diagnostic efficacy of serum 25（OH）D level alone and in combination with the inflammatory factors PCT,CRP and IL-6 on AECOPD by comparing the differences in the AUC of serum 25（OH）D level alone and in combination with the inflammatory factors PCT,CRP and IL-6 for the diagnosis of AECOPD in patients with AECOPD.Results There were no significant differences in age,sex,BMI,or smoking history between patients in the AECOPD group,or in the SCOPD group,and those enrolled in the CON group（P>0.05）,comparison of the course of the AECOPD group and SCOPD patients,no statistically significant difference（P>0.05）;The serum 25（OH）D levels in the AECOPD and SCOPD groups were lower than in the CON group（P<0.05）,while the PCT,CRP,and IL-6 levels were higher than in the CON group（P<0.05）;The serum25（OH）D level of the AECOPD group was lower than SCOPD group（P<0.05）,while the serum PCT,CRP,IL-6 levels were higher than SCOPD group（P<0.05）;The FEV₁,FEV₁/FVC,FEV₁%pred of patients in the AECOPD group and SCOPD group were lower than those in the CON group（P<0.05）,the FEV₁,FEV₁/FVC,FEV₁%pred in the AECOPD group were lower than those in the SCOPD group（P<0.05）;In AECOPD group,the serum 25（OH）D level was significantly negatively correlated with PCT,CRP,IL-6,and GOLD grades（P<0.05）,and significantly positively correlated with FEV₁,FEV₁/FVC,and FEV₁%pred（P<0.05）;The AUC of serum 25（OH）D level alone for diagnosing AECOPD was 0.776,and the AUC of combined PCT,CRP,IL-6 and the four co-diagnosing AECOPD were respectively 0.848,0.827,0.816,0.887.Conclusions The prevalence of vitamin D deficiency is higher in patients with AECOPD.The serum 25（OH）D level is significantly lower in patients with AECOPD than in stable COPD and healthy people,and is significantly correlated with inflammatory factors such as PCT,CRP,IL-6 and lung function indicators such as FEV₁,FEV₁/FVC and FEV₁%pred.Serum 25（OH）D level can effectively differentiate between acute exacerbations and stable phase of COPD,and is of clinical value in assessing the severity of disease in patients with AECOPD and in the quantitative diagnosis of AECOPD.Serum 25（OH）D can be used alone or in combination with inflammatory factors serum PCT,CRP,IL-6 as potential biological indicators for the diagnosis of AECOPD.