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 of LABA permits more participants on minimum maintenance ICS to reduce ICS. The precise magnitude of the ICS dose reduction requires further study.