Differential effects of maintenance long-acting β-agonist and inhaled corticosteroid on asthma control and asthma exacerbations

Abstract

Combination therapy with long-acting beta-agonists (LABAs)/inhaled corticosteroids (ICSs) has become established as effective maintenance treatment for asthma. To compare and contrast the efficacy and safety of LABAs/ICSs against different maintenance ICS strategies in adults with asthma. Cochrane systematic reviews of randomized controlled trials (to April 2004) were identified that compared the addition of LABA to ICS against 3 inhaled corticosteroid strategies: (1) a similar dose (n = 4312 subjects), (2) a higher dose (n = 4951), and (3) a similar dose in steroid-naive subjects (n = 968). The outcomes evaluated were asthma exacerbations, asthma control, and adverse effects. Pediatric studies were excluded. The addition of LABA to ICSs significantly reduced the risk of exacerbations compared with a similar ICS dose, number needed to treat = 18. The effects of LABA/ICSs on exacerbations compared with the other maintenance inhaled corticosteroid strategies were not statistically significant. LABA added to inhaled corticosteroids led to significant improvements in asthma control compared with all 3 maintenance ICS strategies. There was an increased risk of tremor with LABA/ICSs that reached significance for initial therapy, number needed to harm = 21, and compared with higher ICS doses, number needed to harm = 74. Maintenance asthma therapy with LABA/ICSs has differential effects on asthma control and asthma exacerbations. The greatest benefit and least harm of LABAs comes when they are added to a similar ICS dose in adults with symptomatic asthma.