A study has found that about half of children diagnosed with severe asthma initially no longer had it after 3 years, and asthma severity decreased equally in both boys and girls over time.
Severe asthma has been defined as having symptoms that remain uncontrolled despite having a specialist oversee treatment with high-dose inhaled corticosteroids plus a second controller and/or systemic corticosteroids. “While severe asthma affects only about 5 to 10% of children with asthma, these patients experience tremendous morbidity,” explains Kristie Ross, MD. “Severe asthma care accounts for about 50% of asthma-related healthcare in children, with much of that driven by frequent and severe exacerbations.”
Previous research has shown that mild to moderate asthma improves during adolescence, but longitudinal data on children with severe asthma are lacking. “Studies have shown that asthma is more severe and more prevalent in boys than girls, but the disease is more severe and more prevalent in women than in men,” explains Dr. Ross. More information is needed on the natural history of severe asthma in children.
For an article published in the Journal of Allergy and Clinical Immunology, Dr. Ross and colleagues prospectively studied whether well-characterized children with severe asthma improve during adolescence during 3 years of study. Using data from the longitudinal Severe Asthma Research Program (SARP) III pediatric cohort, the authors examined asthma severity changes over time in both male and female adolescents and assessed the possibility of potential predictors of resolution.
According to Dr. Ross, the SARP III study enrolled a cohort of children with asthma enriched for minorities and for children with severe asthma using international definitions. “We extensively phenotyped children at enrollment, which included assessing pubertal status and responsiveness to intramuscular steroids,” she says. “Children were then followed the children prospectively for 3 years and assessed for symptoms, lung function, medication use, and exacerbation rates.” In total, the analysis included 116 male and 71 female children, 111 (59%) of which had severe asthma.
According to the study, from year to year, there was a decrease in the proportion of children who met the criteria for severe asthma. “We were surprised to find that fewer than half of children who had severe asthma at enrollment were still classified as severe at the end of the 3-year follow-up period,” says Dr. Ross. After 3 years, only 30% of patients in the study met the criteria for severe asthma. “We saw improvements in almost all components of asthma severity, including symptom burden, exacerbation rates, and use of controller medications,” adds Dr. Ross. “Lung function was the only component that did not change.”
The study also found that boys and girls were equally likely to have resolved asthma (33% vs 29%) during longitudinal follow-up in adolescence. “Improvements were seen equally in boys and girls despite our predetermined hypothesis at the outset of the study that boys would improve more than girls,” says Dr. Ross. More longitudinal studies will be required to investigate why there was essentially no difference in the probability of severe asthma resolution between male and female participants.
Dr. Ross notes that children with higher eosinophil counts at enrollment were more likely to have their asthma improve. Children with a peripheral eosinophil count of 436 cells/μL or higher were more likely to have their severe asthma resolution of (Table). “This is consistent with other work showing that atopy is a more consistent finding in pediatric than adult severe asthma,” Dr. Ross says.
The study group noted that their findings may be important for planning therapeutic trials in this patient population. “Although further study is needed to determine whether our findings represents a ‘honeymoon’ period or permanent improvement that is sustained into adulthood, it is reassuring that many children with severe asthma will experience improvements in their disease during mid to late puberty,” says Dr. Ross. “Our findings may also help clinicians feel more comfortable following asthma guidelines to wean controller therapies once control is obtained, even in children with a history of severe asthma.”