Prevalence of Eosinophilia in Chronic Obstructive Pulmonary Disease Exacerbation

Chronic Obstructive Pulmonary Disease (COPD) is a major cause of morbidity and mortality worldwide. Objectives: To determine the prevalence of eosinophilia in COPD exacerbation, and to evaluate its association with exacerbation severity. Methods: This cross-sectional study was conducted at the Department of Pulmonology, Indus Hospital and Health Network, Karachi, Pakistan, during April 2024 to September 2024. A total of 141 diagnosed cases of COPD patients were analyzed. Eosinophilia was labeled as a blood eosinophil count ≥ 2%. Stratification analysis was performed to observe the effects of effect modifiers on the prevalence of eosinophilia, applying Chi-square or Fisher's exact test, taking p<0.05 as statistically significant. Results: In a total of 141 patients, 101 (71.6%) were males, and the median age was 62.0 (52.0-71.0) years. Monthly family income was classified as low in 80 (56.7%) patients. Smoking status was ‘never smoked’ in 65 (46.1%), ‘ex-smoker’ in 61 (43.3%), and ‘current smoker’ in 15 (10.6%) patients. Hypertension and diabetes mellitus were reported in 92 (65.2%) and 73 (51.8%) patients. Eosinophilia was identified in 58 (41.1%) patients.  Smoking status differed significantly with respect to the prevalence of eosinophilia (p=0.024). Severity of COPD exacerbation differed by eosinophilia status, as increasing severity was significantly associated with eosinophilia (p<0.001). Conclusions: Blood eosinophilia was frequently observed among patients admitted with COPD exacerbation and showed a significant association with smoking status and exacerbation severity.