Distribution of type-2 biomarkers and association with disease traits in patients with COPD, Data from the BREATHE Cohort

<bold>Background:</bold> Measures of type-2 inflammation are increasingly recognized as important prognostic and treatment-related biomarkers in patients with COPD. Data on the distribution of type-2-biomarkers and their association with clinical traits are sparse. <bold>Aim:</bold> To describe the distribution and overlap of blood eosinophils (B-Eos) and Fractional Exhaled Nitrogen Oxide (FeNO) as well as the association with clinical characteristics in a population of patients with COPD. <bold>Methods:</bold> This is a post-hoc analysis of the BREATHE cohort. BREATHE is a cross-sectional study of patients with airway symptoms referred for specialist evaluation over a 12-month period. Patients were included in the analysis if: FEV1 < 80%, FEV1/FVC < 0.7, ≥ 10 pack years and debut of symptoms > 40 years. Patients were grouped based on B-eos < or ≥ 0.3x109/L and FeNO < or ≥ 25ppb. Data on lung volumes, COPD Assessment Test (CAT) and exacerbation history were included for analysis. <bold>Results:</bold> A total of 215 patients were included. 58.6 % had low B-Eos/low FeNO, 11.6 % had low B-eos/high FeNO, 20.9 % had high B-Eos/low FeNO and 8.8 % had high B-Eos/high FeNO. Patients with high B-Eos/high FeNO had a higher CAT-score (median (IQR): 23 (14-27) vs. 14 (10-20), p=0.02), reported more cough (p=0.03), had more frequent exacerbations (p=0.03) and tended to have smaller static lung volumes (p=0.06) compared to patients with low B-Eos/low FeNO, but they did not differ in age, sex, BMI, FEV1 and smoking history. <bold>Conclusion:</bold> More than 40 % had at least one increased marker of type-2 inflammation. Having both elevated FeNO and blood eosinophils was related to a higher burden of symptoms and more frequent exacerbations.