Prevalence of the eosinophilic phenotype among severe asthma patients in Brazil: the BRAEOS study

Objective: To assess the prevalence of the eosinophilic and allergic phenotypes of severe asthma in Brazil, as well as to investigate the clinical characteristics of severe asthma patients in the country. Methods: This was a cross-sectional study of adult patients diagnosed with severe asthma and managed at specialized centers in Brazil. The study was conducted in 2019. Results: A total of 385 patients were included in the study. Of those, 154 had a blood eosinophil count > 300 cells/mm3 and 231 had a blood eosinophil count of = 300 cells/mm3. The median age was 54.0 years, and most of the patients were female, with a BMI of 29.0 kg/m2 and a history of allergy (81.6%). The prevalence of patients with a blood eosinophil count > 300 cells/mm3 was 40.0% (95% CI: 35.1-44.9), and that of those with a blood eosinophil count > 300 cells/mm3 and a history of allergy was 31.9% (95% CI: 27.3-36.6). Age and BMI showed positive associations with a blood eosinophil count > 300 cells/mm3 (OR = 0.97, p < 0.0001; and OR = 0.96, p = 0.0233, respectively), whereas the time elapsed since the onset of asthma symptoms showed an increased association with a blood eosinophil count > 300 cells/mm3 (OR = 1.02, p = 0.0011). Conclusions: This study allowed us to characterize the population of severe asthma patients in Brazil, showing the prevalence of the eosinophilic phenotype (in 40% of the sample). Our results reveal the relevance of the eosinophilic phenotype of severe asthma at a national level, contributing to increased effectiveness in managing the disease and implementing public health strategies.