Long-acting beta2-agonists as an inhaled corticosteroid-sparing agent for chronic asthma in adults and children.

BACKGROUND: The addition of a long acting beta agonist (LABA) to inhaled corticosteroid (ICS) therapy can improve asthma symptoms and reduce exacerbations. The addition of LABA may also have an ICS-sparing effect and permit a reduction in ICS maintenance dose.

OBJECTIVES: To determine the efficacy of adding LABA to maintenance ICS therapy in reducing the requirement for ICS while maintaining control of chronic asthma.

SEARCH STRATEGY: We searched the Cochrane Airways Group trials register and reference lists of articles. Date of last search: November 2004

SELECTION CRITERIA: Parallel RCTs that compared reduced dose ICS in combination with LABA vs ICS alone in asthmatics requiring daily ICS.

DATA COLLECTION AND ANALYSIS: Trial quality was assessed and data were extracted independently by two reviewers. Study authors were contacted for confirmation. Trials were analysed according to the following ICS dose comparisons: a fixed moderate/high dose or a reduced/tapering dose of the same ICS.

MAIN RESULTS: 19 publications describing 10 trials of adults were included in the review. Studies that compared reduced dose (mean 60% reduction) ICS/LABA combination to a fixed moderate/high dose ICS found no significant difference in severe exacerbations requiring oral corticosteroids (RR 1.0, 95%CI 0.76 to 1.32), withdrawal due to worsening asthma (RR 0.82, 95%CI 0.5 to 1.35) or airway inflammation. There were also significant improvements in FEV1 (change from baseline WMD 0.10, 95%CI 0.07 to 0.12), morning & evening PEF and percent rescue free days with LABA. Two studies provided outcomes for a reduced/tapering ICS dose comparison. More participants receiving the LABA/reduced ICS combination achieved a reduction in ICS dose reaching significance in one study. A significant reduction of 253 mcg BDP was achieved in one study.

AUTHORS' CONCLUSIONS: In adults with asthma, using moderate to high maintenance doses of ICS, the addition of LABA has an ICS-sparing effect. The addition ofLABA permits more participants on minimum maintenance ICS to reduce ICS. The precise magnitude of the ICS dose reduction requires further study.