Non-Invasive Screening Tool Developed to Identify Asthma Risk in Younger Children

Myrtha E. Reyna, MSc

A symptom-based screening tool was developed to help identify asthma in children with symptoms as early as age 3.

Primary care tools designed to detect diseases in preschool children are seen as necessary for illnesses such as asthma, a condition that leads to high economic burden and affects about 330 million people around the world. In countries such as Canada, it is the main cause of hospitalization for children.

This asthma screening tool was developed through a study led by Myrtha E. Reyna, MSc, and Ruixue Dai, MSc, from The Hospital for Sick Children’s Department of Pediatrics. Tools such as the Asthma Predictive Index currently exist. However, their use of invasive elements like skin prick tests, which limit detection due to their difficulty in younger children, led the study’s investigators to develop a more practical detection tool.

“In this study, we leveraged data from the CHILD Study to develop a symptom-based screening tool to identify 3-year-old children at high risk of asthma, persistent wheeze symptoms, and health care burden at 5 years of age,” Reyna and colleagues wrote. “To our knowledge, this is the first symptom-based preschool screening tool developed in a cohort of unselected individuals and validated in both general and high-risk cohorts.”

Background

The investigators’ study—known as the CHILD Study—worked to develop a diagnostic tool known as CHILDhood Asthma Risk Tool (CHART). They assessed 3454 eligible women and their offspring through questionnaires and clinic visits across 4 Canadian sites, between January 2008 and December 2012. The research team evaluated the more invasive tests’ predictors through a blood eosinophil test by 1 year and a skin prick test by 3 years of age.

Children identified through CHART as being high, moderate, or low risk symptoms were reported before 3 years of age. As part of the program, each group was given follow-up instructions. Asthma predictors were tested over the course of the study, which included:

• Using inhaled corticosteroids or bronchodilators
• Both the timing and number of wheezing or coughing episodes
• Using oral corticosteroids
• Number of emergency department (ED) visits and asthma-related hospitalizations

The investigators classified high risk children as those with 2 or more wheezing episodes within the past year, concurrent with asthma medication, ED visits, hospitalizations, or frequent dry cough. Those classified as low risk exclusively had cough episodes or primarily cough episodes in addition to 1 wheezing episode that had taken place prior to the past year.

The research team conducted their analyses to predict persistent wheeze, asthma, and health care burden by age 5 by separately using mAPI, in-study physician diagnosis, parent-reported external physician diagnosis, and CHART. They performed external validation in a general population cohort, the Raine Study, and a high-risk cohort, CAPPS. The investigators measured predictive accuracy by specificity, sensitivity, positive or negative predicted values, and area under the receiver operating characteristic curve (AUROC).

Study Findings

The investigators found that among the 2511 children with enough data to use CHART by 3 years of age, 64.9% were White, 52.7% were male, and all had a mean age of 3.08 years. Among this group, 93.7% (2354 in total) could provide outcome data by age 5.

When the investigators applied CHART applied in the CHILD Study by age 3, it ended up outperforming the mAPI as well as physician assessments in its predictions of health care needs like ED visits or hospitalization for wheeze or asthma (AUROC, 0.70; 95% CI, 0.61 - 0.78), predictions of persistent wheezing (AUROC, 0.94; 95% CI, 0.90 - 0.97), and predictions of an asthma diagnosis (AUROC, 0.73; 95% CI, 0.69 - 0.77).

The researchers even found that the screening tool was similarly successful in its prediction of persistent wheezing in both the Raine Study for children at 5 years (AUROC, 0.82; 95% CI, 0.79 - 0.86) and CAPPS at 7 years (AUROC, 0.87; 95% CI, 0.80 - 0.94). They therefore recommended CHART as a tool for the identification of children who may have needs such as preventative therapies, control of asthma symptoms, and general health monitoring.

“It is important to note that CHART is designed as a pragmatic screening tool to help busy primary care clinicians identify the small proportion of children at high risk for persistent wheezing (7% in our population) among all children who report wheeze (42% at any time point),” they wrote. “Once children are identified as being at high risk, clinicians will need to evaluate this smaller group for both severity and endotype of asthma.”

This study, “Development of a Symptom-Based Tool for Screening of Children at High Risk of Preschool Asthma,” was published on JAMA Network Open.