A27-07 Peripheral Blood Eosinophilia Predicts Lung Function Impairment in Nigerian Children With Asthma

Abstract Rationale Eosinophilic asthma (EA) is a distinct phenotype characterized by elevated eosinophil counts and chronic airway inflammation. In pediatric populations, EA has been associated with increased risk of airway remodelling and progressive lung function decline. In resource-limited settings, peripheral blood eosinophilia may serve as a cost-effective and accessible biomarker for identifying children at risk of poor asthma outcomes. This study aimed to evaluate the relationship between peripheral blood eosinophil levels and spirometric lung function, interpreted using Global Lung Function Initiative (GLI) reference equations in Nigerian children with asthma. Methods A hospital-based cross-sectional study was conducted at the Paediatric Asthma Clinic of Federal Medical Centre, Umuahia. Children aged 6 to 17 years with physician-diagnosed asthma were consecutively recruited. Peripheral blood eosinophil counts were measured using automated hematology analyzers. Spirometry was performed in accordance with ATS/ERS standards, and lung function parameters including FEV1, FVC, and FEV1/FVC, were converted to z-scores using GLI-2012 reference equations for African ancestry. Abnormal lung function was defined as a z-score below the lower limit of normal (LLN), i.e., z < -1.64. EA was defined as an eosinophil count ≥450 cells/mm³. Asthma severity and control were assessed using validated questionnaires. Results Of 176 children enrolled, 56 (31.8%) met the criteria for EA. Children with EA had significantly lower mean zFEV1 (-1.82 ± 0.65) and zFVC (-1.67 ± 0.71) compared to those without EA (zFEV1: -0.94 ± 0.58; zFVC: -0.88 ± 0.63; p < 0.01). A higher proportion of children with EA had FEV1 and/or FVC values below the LLN (62.5% vs. 34.2%, p = 0.018). Logistic regression showed that EA was associated with a twofold increase in the odds of abnormal spirometry (OR = 2.06 for FEV1; OR = 2.34 for FVC). No significant association was found between EA and asthma severity or control scores. Urban residence was independently associated with EA (OR = 3.86, p = 0.005). Conclusions Peripheral blood eosinophilia is a strong predictor of GLI-defined lung function impairment in children with asthma, even in the absence of clinical severity. These findings support the use of eosinophil counts and GLI-based spirometry interpretation as complementary tools for early identification of children at risk for airway remodelling. In low-resource settings, this approach may guide timely initiation of anti-inflammatory therapy and improve long-term respiratory outcomes. This abstract is funded by: self