Simple tool allows doctors to screen children at risk of asthma

A McMaster University-led research team has developed a simple symptom-based screening tool that detects asthma risk in young children.

It avoids the current conventional tools that are time-consuming and invasive, requiring skin pricks, and blood samples.

Researchers reviewed data from 2,354 children for symptoms using the CHILDhood Asthma Risk Tool (CHART). The tool classifies children’s risk of future asthma and persistent symptoms as high, moderate or low, using data gathered before their third birthdays and recommends appropriate follow-up actions for each group.

All children screened by CHART are participating in the Canadian Healthy Infant Longitudinal Development (CHILD) Cohort Study. Launched in 2008 at McMaster, CHILD is tracking the physical, social and cognitive development of nearly 3,500 Canadian children from before birth.

“Asthma affects nearly 330 million people worldwide, carries a heavy healthcare cost and is the leading cause of hospitalization among kids in Canada, especially kids under five,” said Padmaja Subbarao, adjunct professor of the Departments of Medicine at McMaster and CHILD’s director.

“Earlier detection of this condition will allow doctors to treat kids sooner, so they will suffer less and avoid going to the hospital, thus also lowering costs to the healthcare system.”

CHART predicted with 91 per cent accuracy those children who would have persistent wheezing, a key indicator of asthma, by five years old. This was done by using information including wheezing and coughing episodes, use of asthma medications and related hospital visits at three years old.

Of those children evaluated by CHART to be at high risk of asthma at three years old, 50 per cent were diagnosed with asthma two years later by clinicians participating in the study.

The research has been published in the Journal of the American Medical Association.

“We believe the tool is actually even more accurate at predicting asthma than this number suggests,” said Malcolm Sears, co-senior author of the study, McMaster professor emeritus of medicine and CHILD’s founding director.

“Because of various ambiguities in the way asthma is clinically defined, it is likely that a number of these young kids have asthma that remains formally undiagnosed,” he said.

“Regardless of an official asthma diagnosis, persistent wheeze symptoms have been linked to lower lung function, chronic lung disease, and the same kind of health care utilization as asthma; persistent wheeze also requires similar monitoring and treatment, so the value of the tool’s predictive capacity is unquestionable.”

CHART was also found to be more accurate at predicting persistent wheezing, asthma, and related health care usage than other standard diagnostic methods, including physician assessments and the standard modified Asthma Predictive Index (mAPI) test.

Co-first author Myrtha E. Reyna-Vargas said that conventional asthma tests are difficult for children, as they are invasive and take time, requiring skin pricks, blood samples and lung function tests.

“The beauty of CHART, the new tool we have developed, is that it can be used by family doctors or nurses in a low-resource primary care setting,” said Reyna-Vargas, a biostatistician at SickKids.

“It is non-invasive; it can be done on-the-spot and in-the-moment; it is cost-free, and it requires no special equipment. Now that we have shown CHART’s benefits in the CHILD study, we are working towards validating its use prospectively in clinical practice.”

“We designed CHART to be a pragmatic screening tool for the use of busy primary care givers,” said co-first author Ruixue (Vera) Dai, a biostatistician at SickKids.

“With information that can be easily gathered, CHART could be incorporated into electronic medical records as a routine assessment. These kids can then be evaluated more closely, their conditions treated and managed better, and many hospitalizations can be avoided,” she said.

“To our knowledge, this is the first study to develop a non-invasive tool for early detection of asthma and persistent wheeze in a general population, and that has subsequently been validated in general and high-risk cohorts.”