Beta-Agonist in Mild Asthma (BAGS) Trial
Objectives:
An important question in current asthma research is
whether regularly scheduled treatment with inhaled ß-agonists in
asthmatics produces adverse effects on asthma control. Because an estimated
60-70% of patients with asthma have mild disease and are treated only with
inhaled ß2-adrenergic agonists of medium duration, a firm basis upon
which to make treatment recommendations for this large number of patients was
critically needed. Therefore, the ACRN developed a protocol to test the
following null hypothesis: In patients with mild asthma, whose only asthma
treatment is inhaled ß-agonists, addition of regular inhaled
ß-agonist treatment to treatment on an "as needed only" basis will result
in no effect on asthma control.
Subjects and Design:
Patients with mild asthma, and with an FEV1 >= 70%
predicted using ß-agonists as their sole therapy, were recruited and
followed for a 6-week single-blind run-in period during which they took a coded
placebo inhaler, 2 puffs QID. A Chronolog TM recording device was used to
assure compliance and all patients were provided "open label" albuterol for
rescue use. If, after the run-in period, patients were compliant and still met
entry criteria, they were randomized to receive either albuterol or placebo, 2
puffs QID via the Chronolog TM during a 16-week double-blind treatment period,
which was followed by a 4-week "run-out" period during which patients received
single-blind QID placebo. The primary outcome variable was AM peak expiratory
flow (PEF) (measured using a Mini-Wright TM peak flow meter), with multiple
secondary outcome variables including PM PEF, AM-PM PEF variability, asthma
symptom scores, rescue albuterol use, FEV1, including response to albuterol,
methacholine PC20, quality of life, asthma exacerbations, and treatment
failures. Power analysis had indicated that 200 subjects would be required for
an 80% chance of detecting a difference in AM peak flow of 25 L/min. Enrollment
began in December 1994 with a target of 250 randomized patients (allowing for
20% withdrawal). The last subject was enrolled in July 1995, and the trial
ended in February 1996. Of the 319 subjects recruited, 255 (33% minority, 56%
female) were eligible for randomization to receive double-blind treatment (126
in the regular use group and 129 in the as-needed group). Groups were well
matched for all inclusion criteria. Twenty-five patients dropped out of the
trial, yielding 230 subjects who completed it. Compliance with inhaled
medication was > 80%, and more than 99% of the scheduled clinic visits were
kept.
|
|
|
Study Website |
|
Study Documentation |
|
Data Distribution Agreement |
|
|
|
|
|
|
|
|
|
|
|
|