Background- Blood eosinophil count (BEC) is an important biomarker that predicts response to inhaled corticosteroids (ICS) and frequency of acute exacerbation in patients with COPD. The current cut-off value of 300 cells/µL to decide the use of ICS is based on western data. We aimed to determine BECs in healthy, asthmatic, and COPD Indian populations.  

Methods - Healthy subjects who came for routine health check-ups, physician-diagnosed asthmatics, and COPD subjects who came for routine follow-ups were invited to participate in this study in this nationwide cross-sectional study from 24 sites across India. Absolute BEC was obtained from accredited laboratories.

Results - Table 1 lists the median (IQR) BEC levels among 3,763 healthy, asthmatics, and COPD subjects across India. Age, gender and smoking habits had no correlation with BEC.

Conclusion - Compared to the western population, Indians have significantly higher blood eosinophil counts. The current recommended cut-off value of 300 cells/µL to decide the use of ICS for COPD patients may not be appropriate for the Indian population. The high BEC could be attributed to parasitic infection and /or exposure to air pollution.