Clinical and functional characteristics of children with asthma based on bronchodilator responsiveness

<bold>Introduction:</bold> Assessing lung function, including Bronchodilator Responsiveness (BDR) testing, is crucial for managing asthma in children. Nevertheless, there is limited data on the bronchial tone response to a ß2-agonist in children with known asthma and no baseline Obstructive Ventilatory Defect (OVD) on spirometry. <bold>Objective:</bold> To compare the clinical and functional characteristics of children with asthma based on their BDR. <bold>Methods:</bold> It was a cross-sectional comparative study involving Tunisian children with asthma and no baseline OVD on spirometry. The clinical and anthropometric data were collected. All patients underwent pre and post-bronchodilator (PBD) spirometry measuring FEV1, FVC, and FEV1/FVC ratio. A change of >10% relative to the predicted value for FEV1 or FVC indicates a positive BDR (ATS/ERS 2021). The study population was divided into 2 groups: G1 included patients with positive BDR and G2 comprised patients without positive BDR. <bold>Results:</bold> The study population included 54 children with male predominance (59.3%). Means of age and BMI were 10.46±2.76 years and 18.56±3.96 kg/m², respectively. There were no significant differences in environmental conditions such as humidity and pollution, neither in respiratory symptoms nor in passive smoke exposure. For spirometric data, there were significant differences (p<0.05) between G1 and G2 in FEV1/FVC ratio (81.61 ±3.6 in G1 vs 83.9±3.7 in G2), FEV1postBD (%) and in FVCpostBD (%). <bold>Conclusion:</bold> Our study emphasizes the significance of assessing BDR in children with asthma, particularly in those without a baseline obstructive ventilatory defect, to tailor treatment strategies and enhance disease management.