The role of blood eosinophiles in chronic obstructive lung disease (COPD) patients who use inhaled corticosteroids

Purpose: In this study, our goal was to determine the role of blood eosinophiles in Chronic Obstructive Lung Disease (COPD) patients who use inhaled corticosteroids. Results: Of 380 patients who meet the inclusion criteria have been included. 89.2% were male and median age was 66.9. Our study has found that 23.4% of COPD patients were using long term oxygen therapy (LTOT), 28.9% were active smokers and 72.6% had at least one comorbidity. During their follow-up 45.3% of patients had at least one COPD exacerbation with pneumonia. The most affected zone were right lower zone and 57% of cases were confined in one zone only in chest radiograph. 85% of the patients had eosinophile count lower than 300 cells per mililiter and 79.7% had eosinophile percentage lower than 2% blood leukocyte. Despite these findings, 80% of the patients had been using inhaler treatment with ICS. Despite this overtreatment, there was no significant relationship between ICS use and the presence of pneumonia. It was found that empirical antibiotherapy changes were made more frequently, pneumonia was more severe and hospital stay was longer in patients using ICS treatment. Being older than 65 years, male sex, having solid organ malignancy and blood eosinophile count lower than 150 have been found correlated with pneumonia. Having pneumonia was correlated with higher rates of mortality compared to patients without pneumonia in COPD patients. Conclusion: We have found that in COPD patients, there is no relation with ICS usage and blood eosinophile count and percentage, although ICS usage was found related with higher pneumonia severity and frequency of ampirical antibiotherapy change. Eosinophile count and percentage have been found inversely proportional with developing pneumonia and this is more prevalent if blood eosinophile is lower than 150. We recommend that in clinical setting, caution is advised when prescribing ICS to patients with 150 blood eosinophile count.