Asthma is a common, chronic inflammatory airways disease characterised by a clinical syndrome of bronchial hyperresponsiveness, inflammation, and reversible airflow obstruction. In the real-world asthma management and prevention, the principal guidelines GINA 2023 categorise asthma as mild, moderate, and severe.

The patients with severe uncontrolled asthma are characterised by the need for multiple and high-dose drugs for treatment (GINA step 5). It is associated with a greater consumption of economic resources compared to moderate or mild asthma. Type 2 inflammation is found in most patients with severe asthma. Two inflammatory patterns have been identified in type T2 inflammation, i.e., high T2 inflammation (present in allergic and eosinophilic asthma) and low T2 inflammation.

The BREATHE study will describe demographic data, biomarker expression, symptoms, concurrent clinical characteristics and comorbidities, treatment patterns, and access to healthcare for the general population and by previously specified subgroups, according to GINA 2022 definitions of T2 and non-T2 inflammation. The results generated from this study will be instrumental in driving scientific discussions with local experts on the heterogeneity of severe asthma and the importance of deep investigation of patients, to ultimately choose the right treatment for the right patient. Moreover, study results may facilitate interactions with health authorities, such as payer groups, regarding the implementation of novel treatments, as an epidemiological reference on the prevalence of asthma endotypes. Furthermore, this study will generate data from the national territory of Portugal.