Diagnostic value of IgE, fractional of exhaled nitric oxide, and peripheral blood eosinophils in adult bronchial asthma and their relationship with disease severity.

Objective: To investigate the diagnostic value of immunoglobulin E (IgE), fractional of exhaled nitric oxide (FeNO), and peripheral blood eosinophils (EOS) in adult bronchial asthma and to analyze their relationship with asthma severity.

Methods: A retrospective analysis was conducted on 336 patients diagnosed with bronchial asthma and admitted to Xi'an Fourth Hospital from January 2022 to January 2024, forming the asthma group. Additionally, another 127 healthy subjects were selected as the non-asthmatic control group. The patients in the asthma group were categorized into a mild asthma group (n=138), a moderate asthma group (n=115), and a severe asthma group (n=83) according to the severity of the disease. Clinical data, lung function indices, and IgE, FeNO, and EOS levels were compared across groups. ROC curves were used to assess the diagnostic value of IgE, FeNO, and EOS levels for bronchial asthma. Spearman's rank correlation analysis was used to analyze the correlation between IgE, FeNO, EOS and other indicators and asthma severity.

Results: The levels of IgE, FeNO, and EOS were significantly higher in the asthma group than those in the non-asthma group, while lung function indices, peak expiratory flow rate (PEF) and forced expiratory volume in 1 s (FEV1), were significantly lower (all P < 0.05). The areas under curve (AUCs) of IgE, FeNO, and EOS for the diagnosis of asthma were 0.79, 0.93, and 0.88, respectively. Significant differences were observed in smoking history, family history of asthma, co-existing allergic rhinitis, and combined atopic eczema across different severity groups (all P < 0.05). Spearman's rank correlation analysis showed that IgE, FeNO, and EOS were positively correlated with asthma severity (all P < 0.05), with values of 0.718, 0.679, and 0.540, respectively.

Conclusion: IgE, FeNO, and EOS are valuable in diagnosing bronchial asthma in adults. Higher levels of IgE, FeNO, and EOS correspond to increased asthma severity, making these biomarkers useful for assessing asthma severity.