Screening Tool Identifies Preschool Children at High Risk for Asthma

The CHILDhood Asthma Risk Tool (CHART) can identify children at high risk for asthma as early as 3 years of age, according to a study in JAMA Network Open.

Researchers sought 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 age 5 years, using data from the CHILD Study, which enrolled women and their offspring from January 1, 2008, to December 31, 2012, at 4 Canadian sites.

Children with a risk for future asthma and persistent symptoms were categorized by CHART as having a high, moderate, or low risk based on symptoms reported before age 3 years. In the CHILD cohort, 3-year diagnoses using CHART, modified Asthma Predictive Index (mAPI), in-study physician diagnosis, and parent-reported external physician diagnosis were analyzed separately to predict persistent wheeze, asthma, and health care burden at age 5 years.

Validation was performed in 2 external cohorts — at age 5 years in the Raine study and at age 7 years in the Canadian Asthma Primary Prevention Study (CAPPS).

Of 2511 children (mean [SD] age at 3-year visit, 3.08 [0.17] years; 52.7% male) with adequate questionnaire data to apply CHART at age 3 years, 2354 (93.7%) had available outcome data at 5 years.

Among 220 children with at least 2 wheeze episodes at age 3 years, 79 (35.9%) continued to experience wheeze at age 5 years. CHART had a higher success rate in identifying children with persistent wheezing vs physician diagnoses at age 5 years, classifying 72 of the children as high risk (sensitivity, 91.1%; area under the receiver operating characteristic curve [AUROC], 0.94; 95% CI, 0.90-0.97). In-study physician diagnosis at 3 years identified 49 of these children (sensitivity, 62.0%; AUROC, 0.79; 95% CI, 0.74-0.85), and mAPI identified 33 (sensitivity, 48.5%; AUROC, 0.74; 95% CI, 0.68-0.80).

The CHART tool predicted the highest proportion of true-positive asthma at 5 years (sensitivity, 50.0%; AUROC, 0.73; 95% CI, 0.69-0.77), followed by in-study physician diagnosis at 3 years (sensitivity, 43.5%; AUROC, 0.77; 95% CI, 0.73-0.81).

CHART also had the highest predictive rate for subsequent health care use at age 5 years, identifying 20% more children with emergency department visits or hospitalizations (AUROC, 0.70; 95% CI, 0.61-0.78) vs mAPI (sensitivity, 45.5% vs 25.0%) and about 10% more than in-study physician (sensitivity, 36.4%) and external physician diagnosis (34.4%).

Regarding the prediction of outcomes in the Raine study, the discriminative ability of CHART was similar to that obtained in CHILD for prediction of persistent wheeze (sensitivity, 72.9%; AUROC, 0.82; 95% CI, 0.79-0.86) and asthma (sensitivity, 48.2%; AUROC, 0.71; 95% CI, 0.68-0.74) and was higher for predicting medication use (inhaled corticosteroid use: sensitivity, 60.8%; AUROC, 0.76; 95% CI, 0.72-0.80; bronchodilator or oral corticosteroid use: sensitivity, 58.7%; AUROC, 0.74; 95% CI, 0.69-0.79) at 5 years.

For the high-risk CAPPS population, CHART had a high discriminative ability to identify children with wheeze continuing to age 7 years; of 28 children with persistent wheeze, 24 were classified as being at high risk at age 2 years (sensitivity, 85.7%; AUROC, 0.87; 95% CI, 0.80-0.94). Of 58 children diagnosed with asthma at age 7 years, 19 were classified as being at high risk at age 2 years by CHART (sensitivity, 32.8%; AUROC, 0.59; 95% CI, 0.52-0.65).

Among several limitations, CHART was developed and validated in children mostly living in urban centers. In addition, the Raine study and CAPPS did not collect all measures required at preschool age to calculate mAPI; therefore, only comparisons between clinical diagnosis of asthma and CHART were conducted in those cohorts. In addition, the sensitivity (50%) and positive predictive value (41.5%) for asthma in CHART were suboptimal for a screening test.

“CHART is a validated tool that, in this diagnostic study, was able to identify children from 2 years of age at higher risk for persistent wheeze and more likely to develop asthma in general and high-risk populations,” concluded the investigators. “The tool could potentially be implemented routinely as part of electronic medical records initiated at infancy as a simple, noninvasive screening tool for children at primary care.”

Disclosure: Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.