Prognostic analysis of eosinophils and inflammatory index in acute exacerbations of chronic obstructive pulmonary disease

Background: Chronic obstructive pulmonary disease (COPD) is among the most frequent causes of Emergency Room (ER) visits due to its deteriorating symptoms. This study aimed to evaluate the association between eosinophil levels, systemic inflammation indices, and prognosis in patients presenting to the ER with acute exacerbations of COPD (AECOPD). Methods: This retrospective single-center study analyzed electronic health records of patients diagnosed with AECOPD according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines who presented to the ER between 2017 and 2022. Eosinophil levels and inflammatory parameters were measured in 549 patients meeting the inclusion criteria, and their associations with clinical outcomes were assessed. Results: The average age of the study population was 67.5 years, with male patients comprising 57.7% and current smokers accounting for 30.9%. The levels of inflammatory markers, including the systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), neutrophil-to-platelet ratio (NPR) and platelet-to-lymphocyte ratio (PLR), were significantly elevated in patients with low eosinophil levels (p < 0.001). Patients with high levels of inflammatory markers and low eosinophil counts demonstrated increased rates of intensive care unit (ICU) admission and mortality. Receiver operating characteristic (ROC) analysis for mortality revealed a moderately high predictive value for lactate levels (Area under the curve (AUC): 0.805, 95% Confidence Interval (CI): 0.734–0.877) and SII (AUC: 0.785, 95% CI: 0.726–0.844). Among the parameters, lactate levels exhibited the highest specificity (89%), while SII and NLR showed the highest sensitivity (both 95%). Conclusions: High inflammation and low eosinophil levels were associated with worse outcomes, including increased mortality, in COPD patients presenting with acute exacerbations. Smoking status further influences the duration and rate of hospitalization. Aggressive management strategies could improve survival in patients with elevated lactate levels and inflammatory markers.

COPD; Eosinophils; Inflammation index

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