A surprising result of this study was that no significant effect was demonstrated in adolescents on prebronchodilator or postbronchodilator FEV1 over the 3 years of the study. This result was similar to that described in the CAMP trial, which contained a large proportion of adolescent children. Features of asthma are known to improve in many asthmatic children during adolescence, which has coined the phrase “growing out of asthma.” This improvement may explain the lack of change in FEV1 in these patients. Alternatively, the prediction equation for the FEV1 was modeled from the predictions in children and adults, which may have reduced the precision to detect change over time. During puberty, the relationship between height and lung function is more complex that at other periods of life, and assessment of FEV1 percentage of predicted may not be as precise a measure as at other ages Also, adherence with treatment is often worse as children age, which may in part explain the lack of effect of budesonide. so
Despite the benefits of early intervention with inhaled budesonide, postbronchodilator FEV1 values declined in both treatment groups. The differences between the groups were most marked at the initial postrandomization visit at 6 weeks. The reason for the decline in postbronchodilator FEV1 of almost 2% in the placebo-treated patients over this short period, which was not seen in the budesonide-treated patients, is not clear. However, part of the explanation may be the regression to the mean effect that is often seen in clinical trials, when efforts are being made to achieve enrolment criteria (in this study, postbron-chodilator FEV1 values > 80% of predicted). Similar differences in FEV1 between placebo and inhaled corticosteroid treatments by the first study visit have been described in several long-term studies in COPD.
The magnitude of decline in postbronchodilator FEV1 was greater in male compared to female subjects, in adults compared to children, and in smokers compared to nonsmokers.