Association Between Cough Frequency And T2 Inflammation In Severe Asthma

Background: How objective measures of cough relate to Type-2 (T2) biomarkers in severe asthma is unknown. We aimed to assess the relationship between 24-hour cough frequency (coughs per hour [c/h]), and measures of T2 inflammation in severe and mild/moderate asthma patients. Methods: Cough frequency was assessed over 24 hours using the Leicester Cough Monitor. Fractional Exhaled Nitric Oxide (FeNO) and blood eosinophil levels (Eos) were measured and patients were classified into biomarker groups at the time of visit: T2-low (FeNO < 20ppb AND Eos < 150 cells/µl), T2-intermediate: (FeNO ≥ 20ppb OR Eos ≥ 150 cells/µl) or T2-high (FeNO ≥ 20ppb AND Eos ≥ 150 cells/µl). Results: Severe asthma patients (n=41) had higher 24-hour cough frequency values than mild/moderate asthmatics (n=17); geometric mean (SD), 7.1 (2.1) c/h vs 2.5 (4.1) c/h, p=0.002. In severe asthma, biomarker groups differed significantly in terms of cough frequency (p=0.005) with the lowest levels of coughing observed in the T2-low group (figure 1). No significant differences were observed in cough frequency between biomarker groups in mild/moderate asthma. Conclusions: In T2-low patients with severe asthma, cough frequency is low.