Adjustment of Asthma Treatment in Children Based on an Indirect Hyperresponsiveness Test

The aim of the study is to assess the usefulness of the indirect bronchial hyperresponsiveness test (with hypertonic NaCl) in determining the optimal dose of inhaled steroids to maintain asthma control. The study was designed as a prospective, real-life, randomized, interventional study. This single-site study is performed at the Allergology Clinic in Lesko. The study included participants aged 7-15 years who met the eligibility criteria. Eligible participants were selected from a pool of 231 patients with mild asthma, under the care of the Allergology Clinic of the Regional Public Hospital in Lesko (Poland). All participants were diagnosed with chronic mild asthma for at least two years. Subjects initially enrolled in the study had good asthma control maintained for at least 3 months on low / medium-dose ICS monotherapy, with no exacerbations requiring systemic corticosteroids in the previous 3 months, no respiratory tract infection in last month, and an FEV1 above 80% expected. Finally, 108 children were enrolled in the study. They were aged 7-15 years, with active mild asthma, confirmed by the presence of bronchial hyperreactivity and symptoms of asthma, emerging after discontinuation of anti-inflammatory treatment. Participation in the study lasted one year. The study includes: 4-week run-in period (withdrawal phase) after discontinuation of anti-inflammatory treatment (ICS) with clinical symptoms and medication use recording, completed by the patient and parents. At the end of this period, spirometry was performed, bronchial hyperreactivity was assessed with the hyperosmolar salt provocation, and the parameters of inflammation were measured: orally exhaled nitric oxide concentration (NO) and peripheral blood eosinophilia. The anti-inflammatory treatment was then resumed (with ICS in the previous doses). Only patients with active asthma and increased bronchial responsiveness (DRS\>0.55) were qualified for the main study. Stratified randomization was per