Small Airway Dysfunction, a Risk for Exacerbations, is Common in Children With Mild, Well-controlled Asthma in Specialty Care

Abstract Rationale: Although current asthma guidelines have proven effective, many children experience poor asthma control with increased risks of exacerbations and loss of lung function. One possibility could be the failure to recognize the peripheral airways as major sites of airway obstruction. Oscillometry, an in-office procedure, is an effort-independent and effective measurement to identify asthma, uncontrolled asthma, and exacerbation risk in children. It assesses peripheral and central airway function by impedance, including resistance (Rrs) and reactance (Xrs). Although small airway dysfunction (SAD) is most prevalent in children with uncontrolled asthma, studies suggest it is common in well-controlled children with asthma. The purpose of this study was to further establish whether SAD is commonly present in mild, well-controlled children with asthma, and assess characteristics associated with SAD, particularly exacerbations. Methods: This is a post-hoc analysis of a study comparing a new Tremoflo Airwave Oscillometer (AOS) (produced by Thorasys, Montreal, Canada) C2 with the prior FDA-approved device C100. Fifty-three patients from the Allergy-Immunology Department, ages 2 to 7 years, with physician-diagnosed asthma, were evaluated. C100 AOS indices included resistance R7, frequency dependence resistance R7-R19, reactance area (AX), and reactance X7. SAD was identified by a Z score greater than 1.645 RSD, or less than -1.645 for X7. P values indicated the significance of distributional differences between groups based on the Chi-Square Test categorical and independent t-test, and the distributional difference between SAD positive and negative groups. Asthma severity and control were based on National Asthma Education and Prevention Program 2020 guidelines. Results: Nearly half (49.1%) of the children had SAD, despite 84.9% having mild asthma, and 86.8% well-controlled asthma. There was a trend for a higher proportion of SAD-positive children 2-4 years old compared to SAD-negative children (42.3% versus 33.3%), and a greater percentage of males in the SAD-positive group (84.6% versus 63.0%). While 44.2% of the overall population had experienced exacerbations in the previous 12 months, the prevalence was not greater in those SAD-positive. Conclusions: AOS demonstrated that SAD is common in children as young as 2-4 years old with mild, well-controlled asthma. We were unable to demonstrate SAD as a risk factor for previous exacerbations, perhaps due to an inadequate sample size. Prospective studies establishing the value of SAD as an early risk factor for future exacerbations in this susceptible population are needed.

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.