Half of Kids and Teens with Severe Asthma May Grow Out of It with Proper Treatment, Study Suggests
November 10, 2020
Study is first in NIH-funded Severe Asthma Research Program to follow patients over time
Innovations in Pediatrics | Fall 2020
Fully half of children and adolescents being treated for severe asthma will improve over a three-year period, according to a new 11-institution longitudinal study of children and teens ages 6 to 17 being treated for severe asthma. This major finding provides evidence for the idea that some of these patients can “outgrow” their severe asthma while on proper treatment.
“It is good news,” says Kristie Ross, MD, Division Chief of Pediatric Pulmonology at UH Rainbow Babies & Children’s Hospital and lead author of the study. Dr. Ross is also Associate Professor of Pediatrics at Case Western Reserve University School of Medicine.
“Many children who have severe asthma during earlier childhood seem to improve during adolescence,” she adds. “We know these patients did well even though their level of controller therapies decreased over time. It’s reassuring to know that decreasing the dose of controller medicines can be safely done with close monitoring.”
This new study provides important new information for clinicians who manage children and teens with severe asthma, Dr. Ross says. Although severe asthma affects approximately 4 to 5% of children with asthma, it accounts for a disproportionate fraction of the morbidity, mortality and cost of asthma.
For the study, researchers gathered demographic data and data from treatment visits of patients with severe asthma over three years, including asthma control, exacerbations, health care use and any change in medications. At each visit during the study, the patient’s asthma was characterized as severe or non-severe using criteria established by the American Thoracic Society/European Respiratory Society (ATS/ERS). Researchers also compiled data from physical exams, including the patients’ lung function, airway reactivity, fraction of exhaled nitric oxide and eosinophil levels.
Of the 188 children for whom baseline data were collected, annual research visits were completed in 176 (93.6%), 159 (84.6%), and 135 (71.8%) of participants at 12, 24, and 36 months, respectively. Children with severe and non-severe asthma were lost to follow-up in similar proportions at each of the annual visits.
At baseline, 111 (59%) children were characterized as having severe asthma. After three years, only 30% of subjects met the criteria for severe asthma. Subjects experienced improvements in most indices of severity, including symptom scores, exacerbations, and controller medication requirements, but not lung function.
“This decrease in asthma severity was not driven by improvement in any one parameter,” Dr. Ross says.
One factor did, however, predict patients’ asthma improvement status: eosinophil count. Patients with a peripheral eosinophil count of greater than 436 cells/ML were 2.75 times more likely to have their severe asthma resolve than were patients with an eosinophil count below that number.
This was not that surprising, Dr. Ross says, given what is known about the differences between severe asthma in the pediatric and adult populations.
“A substantial majority of kids with asthma and with severe asthma have an allergic phenotype,” she says. “They're sensitized depending on the environment to things like pets, trees, grasses so they have a high eosinophil count. Upwards of 80% of kids that we enroll in asthma clinical research have evidence of allergy, whereas in adults, that phenotype is less common.”
One surprising finding from the study, Dr. Ross says, was on the variable of gender. Because asthma incidence is greater in boys than in girls, the researchers expected that female participants would be less likely to have resolution of their severe asthma than male participants.
”This hypothesis proved incorrect,” Dr. Ross says. “There was no difference in the probability of severe asthma resolution between male and female participants.”
Dr. Ross and her colleagues across 11 institutions hope to keep following the patients in this longitudinal study, while enrolling new patients.
“We are making every effort to continue to follow these young adults into adulthood to see what happens over time with their asthma,” she says. “The program will also be enrolling new subjects, but one of the goals is to continue to follow up. This is the first longitudinal study in the Severe Asthma Research Program (SARP). The first and second iterations of SARP were strictly cross-sectional. The third iteration of SARP, which is what we did the analysis on, is the first time that the subjects were followed over time. So there's great interest in continuing that as we move into the fourth SARP study.”
In the meantime, Dr. Ross says clinicians treating children and teens with severe asthma can take some reassurance from the results of this study.
“If patients who have had severe asthma during earlier childhood are showing signs of improvement, I think clinicians can be reassured that it is reasonable to try to decrease medication strengths,” she says. “If the history and routine lung function testing suggests they are doing well, it is likely they are in the group of adolescents with resolving severe asthma.”
For more information about this study, please email Peds.Innovations@UHhospitals.org.