Published Online November 12, 2012
The goal of asthma care is to achieve and maintain control of the disease at the lowest dose of inhaled corticosteroid. However, a certain proportion of children do not maintain asthma control despite adherence to therapy. Thus it is important to identify the factors that might predict future loss of control before attempting step-down treatment in children with controlled asthma. Impulse oscillometry (IOS) indices of peripheral airway function are associated with asthma control in children. However, an objective tool to assist the clinician in predicting loss of control does not currently exist.
In a recent article in The Journal of Allergy and Clinical Immunology, Shi et al. measured IOS in children 6-17 years old with controlled asthma (n=54). Physicians were blinded to the IOS data and used symptom history and standard spirometry to assess asthma control according to ATS guidelines. No medication change was prescribed and asthma control was assessed again at a follow-up visit 8 to 12 weeks later. IOS indices from the first visit were compared between children who maintained asthma control and those who lost control at the follow-up visit.
The authors found peripheral airway IOS measurements at the first visit were significantly higher in children who lost control (n = 16) compared to those who maintained controlled (n = 38). Cut-points of IOS indices including frequency dependence of resistance (R5-20, 1.0 cmH2O∙L-1∙s) and reactance area (AX, 7.0 cmH2O∙L-1) were able to effectively predict asthma control at the follow-up visit, and correctly classified more than 80% of the population.
These findings showed that IOS indices of peripheral airway function are increased in children with controlled asthma who subsequently lost control in the following 8 to 12 weeks. Thus IOS might be a clinically useful tool to identify children with controlled asthma who are at risk of losing control and might benefit from a change in medication.
The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.