Cross-sectional, observational study to estimate the prevalence of the eosinophilic phenotype for Brazilian patients with severe asthma: the BRAEOS study

Introduction: Patients with severe asthma may present with different phenotypes. Severe eosinophilic asthma patients require frequent use of health care resources and have impaired health-related quality of life. Objective: We sought to determine the prevalence of an eosinophilic phenotype, defined as blood eosinophil counts >300 cells/mm3, for patients with severe asthma in Brazil. Methods: This was a cross-sectional, observational study of adult patients with severe asthma (high dose inhaled corticosteroid [GINA 2018] plus second controller) in routine clinical practice in Brazil. Allergic phenotype was defined as serum IgE>100 IU/mL plus clinical features of allergy. Results: A total of 385 patients were enrolled from 10 Brazilian centers. Most were female (78.4%) and white (57.4%), with a mean age of 53±13 years old. Prevalence of patients with eosinophilic phenotype was 40.0% [95% CI: 35.1–44.9%]. Those were mainly female (76.0%), white (62.3%), with mean age 50±14 years old. Eosinophilic patients presented lower BMI, with no other relevant clinical or demographics differences compared with non-eosinophilic phenotype patients. A high prevalence of allergic phenotype of 62.6% [95% CI: 57.8%-67.4%] was also identified. There was a high overlap between phenotypes as 79.9% [95% CI: 73.5–86.2%] of eosinophilic patients were also allergic. Conclusions: The prevalence of an eosinophilic phenotype for patients with severe asthma in Brazil is high, and these patients present with clinical and demographic characteristics similar to other worldwide populations. The overlap between allergic and eosinophilic phenotypes was common.