Exacerbations after stepping down medication in children with well-controlled asthma: predictive value of spirometry and nitrite/nitrate concentration and pH in exhaled breath condensate

Introduction: The goal in asthma therapy is to achieve control and reduce risk of exacerbations with the lowest treatment. GINA guidelines suggest step down medication when control and lung function during 3 previous months are good. Asthma exacerbations can be difficult to predict; nitrite/nitrate concentrations and pH of Exhaled Breath Condensate (EBC) reflect the inflammation of the airways and could be useful for this. Objectives: To assess the value of spirometry, nitrite/nitrate and pH of EBC in predicting exacerbations after step down therapy in children. Material and Methods: we include asthmatic children with controller treatment who are in conditions to step down (good control and FEV 1 ≥60%). During the first visit medication was reduced and then they were followed every three months for a year. In subsequent visits treatment was adjusted based on control. In basal and later visits ACT, spirometry, and EBC biomarkers were measured and the number of exacerbations were reported. The value of baseline variables to predict exacerbations during follow-up was analyzed. Results: 131 children (mean age 11 ± 2) were included. 33% had at least one exacerbation after step down. Patients with exacerbations on follow up had a lower baseline FEV 1 (88% vs. 97.5%; P = 0.009) and a lower pH in EBC (7.80 vs 7.95; P = 0.027). 78% of children with exacerbations had both FEV 1 Conclusions: Spirometric data and pH in the EBC would help when considering step down therapy in children with well-controlled asthma.