P135 Recognition of eosinophilic asthma: are routine clinical measures useful?

Introduction Eosinophilic airways inflammation, defined as ≥3% sputum eosinophils, in asthma is associated with a risk of severe asthma exacerbations and responsiveness to inhaled and oral corticosteroids and type-2 targeted biologic treatments. The gold standard for measuring airway inflammation is induced sputum analysis, which is not readily available in clinical practice. Blood eosinophils and exhaled nitric oxide (FeNo) are biomarkers of airway inflammation. We investigate whether other, routinely measured, clinical characteristics are associated with eosinophilic airways inflammation. Methods Patients from the severe asthma clinic participated in an observational study in which sputum induction, spirometry, FeNo, blood tests and quality of life questionnaires were performed, as well as relevant medical history being recorded. Patients on oral corticosteroids were excluded. Correlations between baseline clinical characteristics were calculated, and characteristics of eosinophilic and non-eosinophilic patients compared. Results 112 patients were evaluated. Sputum eosinophils were strongly correlated with blood eosinophils and more weakly with FeNO. There was no significant correlation, or difference between eosinophilic and non-eosinophilic patients, in age, gender, pre or post-bronchodilator FEV1, bronchodilator reversibility, smoking status, serum IgE, hospital admissions, self-reported atopy, self-reported aspirin sensitivity or self-reported history of nasal polyps. A summary of the characteristics are shown in table 1. Discussion There are no significant differences in the clinical characteristics of patients with eosinophilic and non-eosinophilic asthma. Measurement of relevant biomarkers is required, in addition to clinical assessment, to identify a steroid-responsive patient population. The blood eosinophil count and FeNO are clinically accessible, useful biomarkers of eosinophilic airways inflammation. Categorical variable are shown as n (%) and p values refer to the Chi-squared test. Otherwise, data shown as mean or median as appropriate. p values refer to t-tests of Mann-Whitney U test as appropriate. *self-reported. BD – bronchodilator. VAS – visual analogue scale (questionnaire)