Combined Diagnostic Value and Mechanisms of Haemophilus Load and Eosinophil Count in Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Objective: To evaluate the synergistic diagnostic value of Haemophilus species load and peripheral blood eosinophil (EOS) count for Acute Exacerbations of Chronic Obstructive Pulmonary Disease (AECOPD) and explore their pathophysiological associations.Methods: Cross-sectional study (Mar 2021-Feb 2024) including 43 AECOPD patients, 43 stable COPD patients, and 43 age/sex-matched healthy controls. Haemophilus load was quantified via RT-qPCR (oropharyngeal/nasopharyngeal swabs); EOS counts via automated hematology analyzers. Statistical analyses included inter-group comparisons, correlation, multivariate logistic regression, and ROC curve analysis.Results: Haemophilus load and EOS were significantly higher in COPD (stable/AECOPD) vs. controls (all P<0.05), with further elevation in AECOPD vs. stable COPD. Both markers correlated positively with AECOPD (Haemophilus: r=0.546; EOS: r=0.562; all P<0.001) and were independent risk factors (Haemophilus OR=2780.091; EOS OR=63414.108; all P<0.001). Combined detection showed superior diagnostic performance (AUC=0.929, sensitivity=81.4%, specificity=90.7%) vs. individual markers (AUC=0.826/0.822; P<0.05).Conclusion: Increased Haemophilus load and EOS are associated with AECOPD, potentially via bacterial infection and eosinophilic inflammation. Their combined non-invasive detection provides high-accuracy AECOPD diagnosis, facilitating early identification, targeted therapy, and improved patient outcomes.