Upper airway symptoms associate with the eosinophilic phenotype of COPD

Background: There is growing evidence that upper airway symptoms coexist with lower airway symptoms in COPD. Still, the prevalence and impact of upper airway disease on the nature and course of COPD remain unclear. We aimed to describe this in a cross-sectional study. // Methods: We examined a cohort of COPD patients with pulmonary function tests, induced sputum, blood eosinophils, atopy tests and computed tomography (CT) of the paranasal sinuses. Lower airway symptoms were assessed using the COPD Assessment Test (CAT), and upper airway symptoms were assessed using the nasal subdomain of the 22-item Sino Nasal Outcome Test (SNOT22nasal). We recruited patients from five sites in Denmark and Sweden. We excluded patients with a history of asthma. // Findings: In total, 180 patients (female 55%, age 67±8 years, forced expiratory volume in 1 s (FEV1 %) 52.4±16.6, Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage: A: 18%, B: 54%, C: 3%, D: 25%) were included in the study. Seventy-four patients (41%) reported high upper airway symptoms (UAS, defined as SNOT22nasal≥6) with a median score of 10 (IQR 8–13). Patients with high UAS reported higher CAT scores (17.4±7.5 versus 14.9±6.6, p<0.05) and displayed higher fractions of eosinophils in blood (median 3.0% (IQR 1.6–4.2%) versus 2.3% (IQR 1.4–3.1%), p<0.05) and in induced sputum (median 1.8% (IQR 0.3–7.1%) versus median 0.5% (IQR 0–1.7%), p