<p>The Value of Inflammatory Biomarkers in Differentiating Asthma–COPD Overlap from COPD</p>

Abstract

To evaluate the accuracy of inflammatory biomarkers in differentiating patients with asthma-COPD overlap (ACO) from those with COPD alone. Methods: Clinical data of 134 patients with COPD and 48 patients with ACO admitted to the First Affiliated Hospital of Xi'an Jiaotong University from January 2016 to June 2019 were retrospectively analyzed. Receiver operating characteristic (ROC) curve analysis was performed to determine the best cutoff values of fractional exhaled nitric oxide (FeNO), blood eosinophil counts (EOS), and neutrophil to lymphocyte ratio (NLR) for differentiating between ACO and COPD alone. Spearman correlation analysis was conducted to evaluate the relationships between these inflammatory biomarkers and the forced expiratory volume in one second/prediction (FEV 1 %pred). Results: FeNO and EOS in the ACO patients were significantly higher than those in the COPD patients (FeNO: median 37.50 vs 24.50 ppb, P < 0.001; EOS: median 0.20 vs 0.10 ×10 9 /L, P = 0.004). FeNO was positively correlated with FEV 1 %pred (r = 0.314, P = 0.030), while NLR was negatively correlated with FEV 1 %pred (r = −0.372, P = 0.009) in patients with ACO. In addition, a positive correlation between FeNO and EOS was also found in ACO, especially in patients without history of inhaled corticosteroids (ICS) use (r = 0.682, P < 0.001). The optimal cutoff value of FeNO was 31.5 ppb (AUC = 0.758, 95% CI = 0.631-0.886) in patients with smoking history, with 70.0% sensitivity and 89.9% specificity for differentiating ACO from COPD. In patients without history of ICS use, the best cutoff value of FeNO was 39.5 ppb (AUC = 0.740, 95% CI = 0.610-0.870), with 58.3% sensitivity and 84.9% specificity. Among patients without history of ICS use and smoking, 27.5 ppb was optimal cutoff level for FeNO (AUC = 0.744, 95% CI = 0.579-0.908) to diagnose ACO, with 81.8% sensitivity and 60.7% specificity, and the sensitivity was improved to 91.7% when FeNO was combined with EOS. Conclusion: The inflammatory biomarkers FeNO and EOS can be used as indicators for differentiating between ACO and COPD alone.

Blood Eosinophils and Clinical Outcomes in Patients With Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Propensity Score Matching Analysis of Real-World Data in China

“…Chis et al reported that the level of blood eosinophils was affected by smoking status in COPD patients ( 20 ). In another study that assessed the accuracy of inflammatory biomarkers in differentiating asthma-COPD overlap (ACO) from COPD, blood eosinophil counts had a higher sensitivity in distinguishing ACO from COPD among patients with a smoking history compared to those without smoking ( 21 ).…”

Human Neutrophil Gelatinase-Associated Lipocalin: A New Biomarker in Asthma-COPD Overlap Syndrome

“…They thougt that NLR may be used as a biomarker to distinguish and diagnose COPD and ACO (34). With a different perspetcive, in a study was found the level of NLR similar in COPD and ACO patients (35). In another study found that the NLR ratio increased in parallel with the severity of COPD (36).…”

The Combined Value of Type2 Inflammatory Markers in Chronic Obstructive Pulmonary Disease

“…It has been reported that FeNO level could be related to pulmonary function and symptom severity of ACO patients in meta-analysis and cohort studies [ 35 , 39 , 40 ]. Some research has illustrated that FeNO and other type2 inflammatory markers, for example, eosinophil count, could be used to differentiate between ACO and COPD [ 41 ]. A positive correlation between age and FeNO level was demonstrated in a previous research [ 7 ].…”