Clinical factors associated with baseline blood eosinophils among patients with asthma or COPD: NOVELTY study

Background: Blood eosinophil count (bEOS) is an important biomarker in obstructive lung disease. NOVELTY (NCT02760329) is a global, prospective, observational study with potential to identify obstructive lung disease phenotypes associated with differential outcomes, using biomarkers and clinical features. Objective: To evaluate factors associated with bEOS in patients with either physician-assigned asthma or COPD in NOVELTY. Methods: A cross-sectional analysis of associations between a single bEOS measurement and other baseline characteristics was performed using univariate and multivariate regression models. Results: Of 4,538 patients with data, the geometric mean (SE) bEOS was 0.16 (0.002) x109/L. Of these, 864 (19%) had EOS ≥300 cells/µL (23% asthma; 14% COPD). High bEOS was positively associated with male sex, ≥2 symptom worsenings in prior 3 months, FeNO, FEV1 reversibility, obesity and frequent mucoid cough, in both asthma and COPD (Figure). For asthma, positive associations with higher bEOS were observed for reduced lung function and physician-assessed severity; for COPD, positive associations were observed with current/former smokers. Associations with FeNO and frequent mucoid cough persisted in multivariate models for both diagnoses. Conclusions: Higher bEOS was independently associated with higher FeNO and presence of frequent mucoid cough regardless of physician-assigned asthma or COPD.