Published online: May 7, 2018
Over 60% of the 334 million people in the world who have asthma have mild disease. Most individuals with mild asthma are stable and require only treatment with low-dose inhaled corticosteroids and/or occasional use of rescue inhalers such as a short-acting beta2-agonist. However, some with mild asthma may progress to more severe forms of disease requiring hospitalizations or emergency room visits, but the clinical features that are associated with disease progression are largely unknown.
Chen and colleagues’ recent paper in The Journal of Allergy and Clinical Immunology: In Practice fills in some critical gaps in knowledge on this front. They identified 70,829 adolescents and young adults with newly diagnosed mild asthma in British Columbia, a province of 4.5 million people in Canada, and followed them for up to 15 years. During every follow-up year, patients were (re)categorized as having mild/dormant, moderate, or severe asthma based on the intensity of asthma treatment and the frequency (and severity) of asthma attacks.
The authors found that most patients with mild asthma remained in the mild category. However, over 10 years, 8% of patients with mild asthma progressed to more severe stages of disease. Death was very rare. The risk factors for disease progression were: 1) frequent use of rescue relievers rather than inhaled corticosteroids for symptom treatment; 2) older age; 3) presence of comorbidities (i.e. disease conditions above and beyond asthma); and 4) the use of single inhaled corticosteroid inhaler rather than the use of combination inhaler therapy consisting of an inhaled corticosteroid and a long-acting beta2 agonist.
This study shows that approximately 1 in 10 patients with mild asthma will progress to more unstable and severe disease. Targeting of disease modifying strategies at this subgroup of patients may reduce the burden of asthma in the community and prevent hospitalizations and emergency departments for asthma.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.