Does severe asthma improve during adolescence?
Published online: October 14, 2019
Severe asthma is asthma that requires a high level of controller medication, yet continues to result in symptoms, low lung function, and/or flare ups. While severe asthma accounts for approximately 4-5% of asthma cases in children, it is associated with more than 50% of asthma related health care costs and results in a high burden for affected children and their families. Other studies have suggested that adolescence and early adulthood is a time when mild to moderate asthma improves, but it is not known if children with severe asthma experience a similar pattern of improvement.
In a paper published recently in The Journal of Allergy and Clinical Immunology (JACI), Ross and colleagues evaluated children with severe and non-severe asthma enrolled in the Severe Asthma Research Program, a study funded by the National Institutes of Health that enrolled 700 children and adults between 2012 and 2015 from 11 centers across the United States. At the time they were enrolled, participating children were assessed for asthma severity, including symptoms, dose of controller medication use, lung function, and frequency of exacerbations. Most children had not yet started or were in the early stages of puberty when they were enrolled. Participants were followed for three years, during which asthma severity and progression through puberty was reassessed every year.
Children received routine care for asthma throughout the study. By examining the rates of severe asthma over time, investigators were able to assess whether severe asthma improves during adolescence. Because asthma is more common and more severe in boys than girls but becomes more common and more severe in women than men after puberty, investigators hypothesized that severe asthma would be more likely to improve in boys than girls as they went through puberty.
The investigators found that more than half of the 110 children who were classified as having severe asthma at baseline no longer met criteria for severe asthma at the end of the three-year period. Surprisingly, boys and girls were equally likely to have their severe asthma improve. Improvements were seen in symptoms, the dose of controller medications, and asthma exacerbations, but not in lung function measures. Children who had higher eosinophil counts (an allergic inflammatory cell) were more likely to have their severe asthma resolve than those with lower eosinophil counts. No other factors predicted improvement.
This is the first study to follow children with well characterized severe asthma through adolescence, and found very high rates of improvement during this time period. Further studies will be needed to determine if asthma severity worsens again later in adulthood.
The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.
Graphical Abstract