In this randomised, double blind, 3 year clinical trial the effects of budesonide in patients with mild persistent asthma for less than 2 years were assessed. 7241 patients in 32 countries aged 5–66 years received either budesonide or placebo once daily for 3 years in addition to their usual asthma medications. At least one severe asthma exacerbation occurred in 198 of 3568 patients in the placebo group but in only 117 of 3597 patients in the budesonide group, a decrease of 44% (p<0.001). Life threatening asthma exacerbations occurred in 24 patients in the placebo group and in nine of those receiving budesonide (p=0.009). Patients in the budesonide group had fewer courses of systemic corticosteroids and more symptom-free days (p<0.0001) and, compared with placebo, budesonide increased postbronchodilator FEV₁ from baseline by 1.48% (p<0.0001) after 1 year and by 0.88% (p=0.0005) after 3 years. In children younger than 11 years the 3 year growth rate was reduced in the budesonide group by 1.34 cm.

This study shows a substantially better outcome in patients with mild persistent asthma treated with inhaled budesonide and may provide new evidence for future therapeutic guidelines. This benefit has to be weighed against possible growth reduction in children.