Twenty-nine RCTs were included in the review (3,592 children). Jadad quality score ranged from 2 to 5.
Asthma/wheezing exacerbations: Sixteen studies reported this outcome (2,805 children). Inhaled corticosteroids was associated with lower incidence of asthma/wheezing exacerbations compared to placebo (RR 0.59, 95% CI 0.52 to 0.67, NNT=7). Test for heterogeneity was non significant.
Secondary outcomes: A lower rate of withdrawals because of asthma/wheezing exacerbations was reported in patients who took inhaled corticosteroids (RR 0.52, 95% CI 0.43 to 0.63). Statistical heterogeneity was non significant. A significant decrease in mean change from baseline symptom score in patients who took inhaled corticosteroids (SMD: 0.93, 95% CI 0.49 to 1.37) was found. Heterogeneity was statistically significant. Other outcomes with significant differences were: mean change from baseline in albuterol use (SMD 0.63, 95% CI 0.30 to 0.63), FEV1 (WMD 0.07L, 95% CI: 0.05 to 0.09) and peak expiratory flow (WMD 13.8L/minute, 95% CI 5.34 to 22.4). Heterogeneity was statistically significant only in mean change from baseline in albuterol use.