The effectiveness of early intervention of inhaled corticosteroids on asthma progression has yet to be established in recent-onset, persistent disease. Therefore, a large worldwide, long-term, doubleblind, placebo-controlled comparison of low doses of inhaled corticosteroids initiated within the first 2 years of a diagnosis of asthma, the Inhaled Steroid Treatment as Regular Therapy in Early Asthma (START) study, was undertaken to determine whether early intervention with low-dose inhaled budesonide in patients with persistent asthma would prevent severe asthma-related events and the accelerated decline in lung function. The main results of the START trial are reported elsewhere, including the initial analysis of the postbronchodilator FEV1, In this report, the first 3-year double-blind part of the study, examining the effects of early intervention on lung function, is described in more detail, with additional analysis.
The study design, methods, and inclusion and exclusion criteria of the START trial are described in detail elsewhere. The study enrolled 7,241 patients aged 5 to 66 years from 32 countries. Patients had asthma symptoms weekly, but not daily, during the 3 months prior to study. These symptoms had to be present for < 2 years (ideally < 1 year). Patients demonstrated airway obstruction by an increase in FEV1 > 12% after a p2-agonist, a fall in FEV1 > 15% after exercise, or a variation > 15% in peak expiratory flow rates over 14 days. The study was approved by all the Research Ethics Boards of participating institutions prior to initiation, and all subjects signed informed consent before bring enrolled into the study.
The patients were randomly assigned to receive either once-daily budesonide or placebo delivered from a dry powder inhaler (Turbuhaler; AstraZeneca; Lund, Sweden). The daily dose of budesonide was 200 |j,g in children aged < 11 years at randomization and 400 |j,g in the others. The placebo was lactose. Changes in concurrent medication, including introducing inhaled or systemic corticosteroids, could be made during the study at the investigator’s discretion to achieve asthma control.
The outcomes measured were change from baseline in pre-bronchodilator and postbronchodilator FEV1 percentage of predicted and in FVC percentage of predicted.