Asthma Control Test Gauges Lung Function, Airway Swelling in Stable Asthma

Children with asthma classified as stable according to the asthma control test (ACT) had significantly higher lung function spirometry results than children whose asthma was not classified as stable, according to the results of a recent study published in the Journal of Asthma.

Whole blood samples were collected from children with asthma to evaluate white blood cell count, eosinophil fraction, levels of total serum immunoglobulin E, and C-reactive protein. Spirometry was performed to determine forced vital capacity, forced expiratory volume in 1 second (FEV₁), and forced expiratory flow between 25% and 75% of forced vital capacity. Associations between blood and spirometry results were then compared between groups stratified by different levels of symptom control according to the ACT.

Among the 441 patients, the mean age was 9±1.8 years. In the controlled asthma group, spirometry results for FEV₁, forced expiratory flow between 25% and 75% of forced vital capacity, and FEV₁/forced vital capacity as well as white blood cell count were significantly higher. Furthermore, fractional exhaled nitric oxide (FeNO) was significantly lower in the controlled asthma group. When other patient demographics were examined, only the provocative concentrations of methacholine causing a 20% fall in FEV₁ was significantly correlated with ACT.

The study authors wrote, “We found that ACT not only reflects lung function, but also airway inflammation by showing a significant difference in FeNO.”

They added, “The results of the present study suggest that ACT and C-ACT can be used as part of the routine evaluation of asthmatic children and as a complement to other tools such as spirometry and FeNO measurement.”

Reference

Lee WY, Suh DI, Song DJ, et al. Asthma control test reflects not only lung function but also airway inflammation in children with stable asthma [published April 10, 2019]. J Asthma. doi:10.1080/02770903.2019.1599386