Eosinophilic and non-eosinophilic asthma: an expert consensus framework to characterize phenotypes in a global real-life severe asthma cohort.

BACKGROUND: Phenotypic characteristics of eosinophilic and non-eosinophilic asthma patients are not well-characterized in global, real life severe asthma cohorts. RESEARCH QUESTION: What is the prevalence of eosinophilic and non-eosinophilic phenotypes in the severe asthma population, and can they be differentiated by clinical and biomarker variables? STUDY DESIGN AND METHODS: This was an historical, registry study. Adult severe asthma patients with available blood eosinophil count (BEC) from 11 countries enrolled into the International Severe Asthma Registry (01/01/2015 to 09/30/2019) were categorized according to likelihood of eosinophilic phenotype using a pre-defined gradient eosinophilic algorithm based on highest BEC, long-term oral corticosteroid use, elevated fractional exhaled nitric oxide, nasal polyps, and adult-onset asthma. Demographic/clinical characteristics were defined at baseline (i.e. 1-year prior or closest to date of BEC). RESULTS: 1,716 patients with prospective data were included; 83.8% were identified as "most likely" (Grade 3), 8.3% were "likely" (Grade 2), and 6.3% "least likely" (Grade 1) to have an eosinophilic phenotype. 1.6% of patients had a non-eosinophilic phenotype (Grade 0). Eosinophilic phenotype patients (i.e. Grade 2 or 3) had later asthma onset (29.1 vs 6.7 yrs; p