Small airway dysfunction and prior exacerbations are common in primarily well-controlled pediatric asthma

Although current asthma guidelines are effective, many children experience poor asthma control. A possible explanation is the failure to identify small airway dysfunction (SAD), a known risk factor for exacerbation.

To assess SAD prevalence by means of oscillometry, its association with previous exacerbations, and whether consideration of SAD and/or previous exacerbations as risk factors aligns with current therapy patterns.

This is a post hoc, retrospective, cross-sectional analysis of 53 primarily mild, well-controlled children with asthma (ages 2-7 years) using the C100 Airwave Oscillometer. SAD was defined for R7-R19, AX, and X7 as a Z score greater than 1.645. High-risk status was defined by SAD and/or more than 1 exacerbation in the previous 12 months. Therapy patterns were compared with risk status.

SAD is seen in 49.1% of the cohort, and 43.3% had previous exacerbations, whereas 74.0% met the criteria for high-risk status. There were no significant differences in demographics, previous-year exacerbations, or treatment patterns among any of these at-risk categories. Only 41% of the children classified as high risk were receiving step 2 or higher therapy.

Our data suggest that SAD and/or previous exacerbation biomarkers are common in primarily symptom-based mild, well-controlled young children with asthma, identifying a phenotype that is potentially at risk for future exacerbations and is frequently unrecognized, as reflected by current therapy patterns.