Discordant associations between Type 2 biomarkers and severity of asthma and COPD

Background Allergic and Type 2 (T2) inflammatory biomarkers are increasingly used to predict outcomes and guide treatment in asthma and COPD. The objective of this cross-sectional study was to determine the prevalence of allergic sensitisation and T2 biomarkers and their clinical associations among patients with diagnoses of asthma and/or COPD in NOVELTY, a large multinational, observational study. Methods Participants were enrolled from primary/specialist care, stratified by physician-assigned diagnosis and severity. We assessed blood eosinophils (B-Eos ≥300 cells/μL), fractional exhaled nitric oxide (FeNO ≥25 ppb), and allergen-specific IgE sensitisation (sIgE ≥0.35 kU·L −1 ; any of 11 aeroallergens). Associations between biomarkers and clinical outcomes were examined using descriptive statistics and multivariable regression models adjusted for age, sex, body mass index, and smoking status. Results Data for all biomarkers were available for 4352 participants (asthma: n=2194; asthma+COPD: n=633; COPD: n=1525). Overall, 63% participants had ≥1 positive biomarker (asthma: 77%; asthma+COPD: 60%; COPD: 45%); only 8%, 4%, and 1% participants, respectively, were positive for all three. Women and current smokers were more likely to be triple negative. Among participants with asthma, having more positive biomarkers was associated with more severe physician-assessed disease, lower lung function, and exacerbations. By contrast, in COPD, having no positive biomarkers was associated with more severe physician-assessed disease and lower lung function. Conclusions Allergic and T2 biomarkers are highly prevalent in asthma and asthma+COPD but less frequent in COPD. Their patterns show distinct associations, sometimes with opposite trends, across diagnostic groups, suggesting distinct underlying mechanisms that differ.