A new predictor to determine the exacerbation and treatment of chronic obstructive pulmonary disease: eosinophil/neutrophil ratio

Abstract

Introduction: COPD is an inflammatory disease characterized by persistent respiratory symptoms and airflow limitation. Currently, it has been demonstrated in some studies that eosinophil and T helper-2 mediated inflammation play a role in the pathophysiology of COPD. Materials and Methods: It was planned to evaluate eosinophilia, eosinophil/neutrophil ratio (ENR), distribution of ENR according to GOLD groups, number of exacerbations in last year, relationship between ENR and the rate of ICS use in COPD patients, and the ENR cut-off value that predicts eosinophilic COPD. This study was planned prospectively in stable COPD patients between July 2017 and December 2017. All patients were divided into two groups as eosinophilic and non-eosinophilic group. Eosinophilia was considered to be > 2% of peripheric blood eosinophils. Results: A total of 206 stable COPD patients (127 eosinophilic and 79 noneosinophilic) were included. Age, gender, BMI, smoking history, mMrc score were statistically similar while average pack-year of smoking was significantly higher in eosinophilic group. ENR was significantly higher in eosinophilic group as expected (p< 0.001). High positive correlation was found between ENR and eosinophilic COPD (r= 0.8, p< 0.001). In Group D, the number of eosinophilic COPD patients is significantly higher than the non-eosinophilic group while the distribution of patients in group A, B, C was similar. Although the PFT findings were similar in both groups, the use of ICS was significantly lower and the number of exacerbations was significantly higher in eosinophilic group. In the ROC analysis, the ENR cut-off value that predicts eosinophilic COPD was found to be 0.32 in all COPD patients (Sens: 93.7%, Specif: 92.4%, AUC- 0.97, p< 0.001). Conclusion: Based on these findings, it is considered that more priority should be given to the use of ICS in COPD patients with high ENR and it can be used as a marker for predicting COPD exacerbation as COPD exacerbations are higher in patients with ENR.