Clinical differences between eosinophilic and non-eosinophilic acute exacerbation of chronic obstructive pulmonary disease (AECOPD), a multicenter cross-sectional study

Abstract

Background AECOPD is highly heterogeneous with respect to etiology and inflammation. COPD with higher blood eosinophils is associated with increased readmission rates and better corticosteroid response. However, the clinical features of eosinophilic AECOPD aren’t well explored. Then, the aim of this study was to investigate the clinical differences between eosinophilic and non-eosinophilic AECOPD. Methods A total of 643 AECOPD patients were enrolled in this multicenter cross-sectional study. Finally, 455 were included, 214 in normal eosinophils AECOPD (NEOS-AECOPD) group, 63 in mild increased eosinophils AECOPD (MEOS-AECOPD) group, and 138 in severe increased eosinophils AECOPD (SEOS-AECOPD) group. Then, demographic data, underlying diseases, symptoms, and laboratory findings were collected. Multiple logistic regression was performed to identify the independent factors associated with blood EOS. Correlations between blood EOS and its associated independent factors were evaluated. Results The significant differences in 19 factors, including underlying disease, clinical symptom, and laboratory parameters, were identified by univariate analysis. Subsequently, multiple logistic regression revealed that lymphocytes%, neutrophils% (NS%), procalcitonin (PCT), and anion gap (AG) were associated with blood EOS in AECOPD. Both blood EOS counts and EOS% significantly correlated with lymphocytes%, NS%, PCT, and AG. Conclusions The blood EOS was independently associated with lymphocytes%, NS%, PCT, and AG in AECOPD patients. Lymphocytes% was lower, and, NS%, PCT, and AG were higher in eosinophilic AECOPD. Our results indicate that viral dominant infections probably were the major etiology of eosinophilic AECOPD. Non-eosinophilic AECOPD was more likely associated with bacterial dominant infections. The systemic inflammation in non-eosinophilic AECOPD was more severe.