The decline demonstrated a Gaussian-like distribution in both treatment groups but with fewer patients in the budes-onide group in the tail with a greater loss in FEV1. Thus, 21.4% of patients in the placebo group had a decline in FEV1 a 10% over the 3 years of the study, while 17.7% of patients in the budesonide group had a similar decline. In the placebo group, there was a 1.6% decline in FEV1 during the first 6 weeks; subsequently, there was on average, a decline by 0.4% per year up to the 3-year follow-up. In the budesonide group, there was a 0.3% increase in FEV1 during the first 6 weeks; subsequently, there was on average a decline of 0.7% per year up to the 3-year follow-up. These results suggest that there is an effect of the asthmatic process on airway remodeling that is either resistant to the effects of inhaled corticosteroids or may require a higher dose than was used in this study. in detail
Inhaled corticosteroids improve some of the airway structural changes that are found in patients with asthma, including the integrity of the airway epithelium, the extent of airway vascularity, and the extent of the extracellular matrix deposition below the basement membrane. Interestingly, these effects were seen with a higher dose of inhaled corticosteroid (an average dosage of inhaled fluticasone propionate of 1,000 ^g/d or budesonide of 800 ^g/d) than was used in the present study. Also, in the study of Sont et al, both clinical outcomes and the reduction in airway extracellular matrix were seen with a higher dose rather than a lower dose of inhaled budesonide. Furthermore, no information exists on the effects of inhaled corticosteroids on some other components, such as the increases in airway smooth-muscle volume.
The FEV1/FVC ratio is a sensitive indicator of airflow obstruction and was improved by treatment with inhaled budesonide in childhood asthma in the CAMP trial. In the present study, reliable results for FVC were not obtained in children and adolescents because stringent efforts were not made in all centers to ensure a sufficiently long expiratory phase of the forced expiratory maneuver. Reliable information was, however, obtained in the adult patients. The results in the adults confirmed that treatment with budesonide significantly attenuated the decline in the FEV1/FVC ratio demonstrated in the placebo group.