Phenotyping moderate asthma earlier by analyzing induced sputum eosinophils, blood eosinophils, and atopy: a...

There has been limited research comparing the inflammatory characteristics of moderate and severe asthma in Brazil. To describe and compare the phenotypes of moderate asthma (MA) and severe asthma (SA) in Brazilian patients.

In this cross-sectional study, we defined SA per the 2014 European Respiratory Society/American Thoracic Society criteria and MA per the 2018 GINA criteria. No participants had other lung diseases, recent respiratory infection, or a recent exacerbation. Asthma was characterized and phenotyped by using validated tests.

Compared to MA (n = 55), SA (n = 51) had more hospital (p < 0.001) and ICU admissions (p = 0.01), worse fixed airflow limitation (FEV₁/FVC post-BD = 0.61; p < 0.001), poorer asthma control (p = 0.001), and reduced quality of life. However, this was not associated with higher activity of inflammation as measured by IS and Beos counts, which were similar. In addition, of the 19 patients with MA who reported ≥ 1 exacerbation in the last year, 12 (63.1%) had residual eosinophilia in induced sputum, compared with 22 (62.8%) of the 35 such patients with SA. The correlation between IS eosinophils and Beos was strong (rs = 0.75, R² = 0.35; p < 0.001), though agreement was moderate. T2 phenotypes were predominant (76% in both groups). However, in the MA group, the prevalence of eosinophilic allergic asthma was higher than that of nonallergic asthma (56% vs. 20%; p < 0.001). In the SA group, those phenotypes had a similar prevalence (41% and 35%, respectively).

Our analysis indicates that most subjects with SA or MA have the T2-high asthma phenotype, primarily allergic eosinophilic, in MA. Significant residual eosinophilic airway inflammation and recurrent exacerbations in some patients with MA suggest the need for further research on the optimal timing for.