Raised blood eosinophils (EOS) is associated with asthma disease severity, and clinical guidelines recommend using it as a biomarker to inform treatment decisions. This study?s objective is to characterize the asthma disease burden and resource use stratified by EOS levels.

Asthma patients, without comorbid lung diseases, were retrieved from the UK biobank, a population-based prospective 500,000 adult cohort, aged 40-70 recruited between 2006-10, and followed until Dec-2019. Differences in the prevalence of atopic comorbidities at baseline, yearly mortality rate, all-cause hospitalizations, and GP visits during follow-up were assessed. The incidence of severe exacerbations was analyzed by multivariate logistic regressions, where confounders were added by stepwise variable selection.

52,742 asthma patients were followed for 10.7 years (±1.4). 14,104 (27%) patients with EOS?300 were older (55.9 vs. 56.3) and had a higher prevalence of males (47 vs 40%) than patients EOS <300. BMI, air pollution exposure, and smoking prevalence were similar. The prevalence of atopic comorbidities (atopic dermatitis, chronic rhinosinusitis with/without polyp and allergic rhinitis) at baseline was significantly higher in patients with EOS?300 (26.6 vs. 18.3%). Patients with EOS ?300 had 1.3 times higher odds of suffering a severe exacerbation than patients with EOS <300, after adjusting for sociodemographic characteristics, smoking status, and atopic comorbidities (95%CI 1.21-1.32, p<0.001). No statistically significant differences were observed in yearly mortality rate, GP visits and all-cause hospitalizations.

Asthma patients with EOS?300 have more atopic comorbidities and more frequent severe exacerbations vs EOS <300.