Metabolic dysfunction is associated with non-eosinophilic asthma phenotype: a retrospective cross-sectional study

Aim: Asthma is a heterogeneous airway disease comprising distinct inflammatory phenotypes with variable clinical characteristics and treatment responses. Increasing evidence suggests that obesity-related metabolic dysfunction contributes to asthma pathogenesis; however, its relationship with eosinophilic asthma remains incompletely understood. This study aimed to evaluate metabolic dysfunction in patients with asthma and investigate its association with the eosinophilic phenotype using multiple insulin resistance-related metabolic indices. Methods: In this retrospective cross-sectional study, 90 patients with asthma and 131 healthy controls were included. Metabolic dysfunction was assessed using body mass index (BMI), homeostatic model assessment for insulin resistance (HOMA-IR), triglyceride-glucose (TyG) index, cholesterol-glucose (CHG) index, and metabolic score for insulin resistance (METS-IR). Eosinophilic asthma was defined as a peripheral blood eosinophil count ≥ 300 cells/µL. Group comparisons and multivariable logistic regression analyses were performed to identify factors associated with eosinophilic asthma. Results: Compared with healthy controls, patients with asthma demonstrated significantly higher BMI, HOMA-IR, METS-IR, peripheral eosinophil counts, and neutrophil-to-lymphocyte ratio (NLR), indicating greater metabolic dysfunction and systemic inflammation. Among patients with asthma, 27.8% were classified as having eosinophilic asthma. Patients with eosinophilic asthma had significantly lower BMI and METS-IR values than those with non-eosinophilic asthma. In the multivariable logistic regression analysis, METS-IR showed an inverse but non-significant association with eosinophilic asthma after adjustment for age, sex, inhaled corticosteroid (ICS) use, and NLR. Conclusions: Metabolic dysfunction was more prevalent in patients with asthma than in healthy individuals. Although eosinophilic asthma was associated with lower BMI and METS-IR values in univariate analyses, these associations were not confirmed after adjustment for potential confounders. These findings suggest that metabolic dysfunction may contribute to asthma phenotypic heterogeneity and warrant confirmation in larger prospective studies.