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

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.

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.

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).

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.