Airway reversibility and inflammation in stable pre- to late-adolescent asthmatics without long-term control...

Objective: Pulmonary function and airway inflammation were investigated in stable pre- to late-adolescent asthmatics without long-term control medications and compared with those in currently medicated asthmatics.Methods: Subjects comprised 34 well-controlled asthmatic children (aged 8.1-18.0 years; group without medication). Flow volume curves before and after inhaling a β2 agonist, a bronchodilator (BD), were compared and fractional exhaled nitric oxide (FENO) concentrations were measured. All patients were attack-free for at least 12 months prior to testing without the use of asthma medications for at least three months. Fifty-one age-matched stable asthmatics with medications at the time of the present study (group with current medication) underwent the same examinations.Results: The rate of children whose respiratory function after BD improved by 20% or more in both the central and peripheral airways (High responder at total airways subtype: HTA) was significantly higher in the group without medication than in that with current medication (17.6 and 2.0%, respectively; p < 0.01). Furthermore, FEV_1.0% pred after BD was significantly lower for HTA than for the low responder subtype in the same group (94.8 ± 3.5 and 104.1 ± 1.5% respectively, p < 0.05). FENO concentrations in the group without medication were high, but not significantly different from those in the group with current medication.Conclusions: Stable asthmatic children without medication include a certain percentage of those with irreversible airflow limitation possibly due to airway remodeling. The control of daily asthma symptoms with long-term control medications may effectively prevent airway remodeling.