In the study of a population of severe asthmatics, not controlled despite the treatment conducted, it was possible to evidence 5 phenotypic groups of patients. According to the refractoriness of the response to treatment, severe asthma may be phenotype in some distinct groups.Other prospective study found a large proportion of severe asthmatics with persistent airway obstruction, despite optimized treatment and systematic follow-up. Small airway involvement and remodelling, characterized by bronchial muscle thickening, appear to be the main culprits for asthma severity and persistent obstruction in this population.A point of interest in the severe asthmatics cohort was the vast majority were female and there were a considerable number of obese. Recent reviews show that the more consistent division of phenotypes in patients with severe asthma is still based on 3 previously described criteria (presence of atopy, eosinophilia and age of onset of asthma) and a more recent criterion for the presence of multi-comorbidities. Heterogeneity is the rule, the presumption of a natural evolution of gravity is not confirmed and the overlap of clusters is frequent. The stability and natural history of the phenotypes is poorly understood, postulating that the inflammatory activation of the severe asma is multifactorial and may resemble that described in the oncology literature.To date, there are no markers that allow prediction of lung evolution of most patients with severe asthma, and which patients are at greater risk of developing persistent or accelerated loss airflow or lung function, factors determining the severity of asthma. It is also unclear whether and how much phenotype-based treatment impact on disease control and prognosis. Future studies will be instrumental in defining how and why. These phenotypes are evolving, leading to the disabling characteristics of severe asthma and what may be the more effective therapeutic approaches for these patients. Since the initiated research group from 2006 has an extensive clinical, functional, inflammatory, tomographic and morphological evaluation of a cohort of patients with severe asthma, the ideal scenario exists to advance the understanding and investigation of the evolution of this rare disease through standardized follow-up.

Inclusion Criteria:

• Moderate to severe asthma (GINA step 3-5), followed in the outpatient clinic
• Non-smokers, smokers or former smokers of ≤ 10 packets per year. For smokers, <10 cigarettes / day and with onset asthma before onset of smoking
• Obese asthma patients BMI>30 kg / m2 FEV1 pre bronchodilator between 50 and 80% predicted
• Normal Chest Xray

Exclusion Criteria:

• Pregnancy
• Patients with a history of neoplasia, HIV + or other comorbidities that may interfere in the the study
• Patients with no understanding of the study procedures or who are not able to give their free and informed consent;
• Patients with other lung diseases such as chronic obstructive pulmonary disease, bronchiectasis, cystic fibrosis, or other lung diseases that may interfere with the study evaluation;
• Non adherence to standard asthma treatment;
• Inability to perform lung function assessment tests;
• Pulmonary exacerbation up to 30 days before the first study evaluation