Clinical Outcome of Mild to Very-mild Asthma With High Sputum Eosinophils and/or High Genetic Risk Score: a Prospective Longitudinal Study

Asthma is a chronic respiratory disease affecting approximately 10% of the population, the majority of patients with very mild to mild asthma. Asthma is characterized primarily by the presence of symptoms clinical variables, reversible airway obstruction and airway hyperresponsiveness. Inflammation is a key factor in the pathophysiology of the disease. Eosinophilic inflammation is the most common type. However, in the literature it is usually associated with more severe and difficult to control asthma. Although mortality associated with asthma has drastically decreased in recent years, several events still occur. Strangely enough, these frequently affect mild asthmatics. Although there is still a misunderstanding in relation to these events, the most recent practice guides have recommended an approach based on the use of inhaled corticosteroids (ICS) in all, including mild asthmatics. This change of therapeutic cap is still debated, but indicates a need for new studies in this population. Recently, the investigators demonstrated that a subgroup of asthma patients with mild asthma had a eosinophilia. The evolution of this subgroup without bronchial obstruction or respiratory symptoms remains unknown. Indeed, it seems imperative to determine the fate of these subjects in comparison with asthma mild non-eosinophilic since it could be a subgroup at risk of poor outcome. The objective of this study will be to examine the course of asthma in very mild to mild asthma patients who exhibit eosinophilic inflammation of the respiratory tract compared to noneosinophilic subjects.

This will be a prospective observational, longitudinal study. Participants for whom a result of induced sputum showing an eosinophil level greater than or equal to 3% was observed at least 1 year ago will be contacted to participate in the study. They will be matched for age, gender and duration of asthma to subjects without eosinophilia. These subjects will not be on bronchial anti-inflammatory medication. They will have a complete evaluation including respiratory function tests, a methacholine challenge and sputum induction. They will also complete questionnaires on controlling their asthma and exacerbations.