Sex differences in severe asthma: Results from severe asthma network in Italy-SANI

Purpose: After adolescence, asthma is more frequent in females than in males due to different hormonal, immunologic, and occupational/environmental factors. The higher prevalence and severity of the disease in females have already been reported in international registries. The aim of this study was to explore the difference in terms of clinical, functional, and biological characteristics between male and female patients with severe asthma in a real-life, registry-based setting. Methods: Baseline data from the Severe Asthma Network in Italy registry were analyzed in 1,123 patients with severe asthma, according to sex. Results: Almost 2/3 of severe asthmatics were female. Late-onset asthma, obesity and gastro-esophageal reflux were more frequent in females than in males, while previous smoking habits and nasal polyposis were more frequent in males. Females had poor asthma control and a higher number of severe exacerbations leading to hospitalization, in comparison to males. Biomarkers of type 2 inflammation (blood eosinophil, exhaled nitric oxide, and serum immunoglobulin E levels) were significantly higher in males than in females. The type 2 profile (defined by a combination of these 3 biomarkers) was significantly more frequent in males than in females. In multivariate analysis, late-onset asthma and a normal body mass index were only independent variables associated with the type 2 profile, while male sex and age showed only a trend toward the association with the type 2 profile. Conclusions: Significant differences may be observed between male and female patients with severe asthma, influencing the asthma pheno-endotyping in both sexes.