Most asthmatic children will be given inhaled corticosteroids to control their asthma. If these are not sufficient, another type of drug, a long-acting beta-2 agonist (LABA) such as salmeterol or formoterol, might be used as well. A new Cochrane review investigated the beneficial and harmful effects of the addition of LABA as a second drug.

The review sought evidence from trials in children and adolescents aged from 2 to 18 years. These children needed to have been taking inhaled corticosteroids for a month or longer, before being randomised to LABA or placebo for at least 28 days of treatment. A total of 25 eligible trials were found, with nearly 5600 children studied. Nearly all the trials had been done by the manufacturer of either the corticosteroids or the LABA.

The authors of the Cochrane review split their review into two main comparisons. One in which the children received the same dose of corticosteroid, whether they were in the LABA or the placebo group; and the other for those trials where the children received an increased dose of corticosteroid if they were not allocated LABA. The bulk of the data was in the former: 24 randomised pairings, with 4600 children. Some trials were in both comparisons.

When compared to the same dose of inhaled corticosteroids alone, the addition of LABA did not lead to a significant reduction in exacerbations requiring oral steroids, or differences in symptom-free days, hospital admission, quality of life, use of reliever medication, and adverse events. But there was a significantly greater improvement in lung function with the addition of LABA and fewer withdrawals from treatment. Similarly, most of the outcomes assessed did not differ significantly between the combination group and the group receiving an increased dose of corticosteroids on their own. But, lung function did seem to be improved with the two drug combination and the children’s growth was greater.

In regard to how their findings should impact on practice, the authors of the Cochrane review conclude that there is not enough evidence at the moment to support the addition of LABA to inhaled corticosteroids, if the goal is to reduce the risk of asthma exacerbations requiring steroids. They call for additional trials to be done urgently to provide the evidence needed by decision makers who face the dilemma of what to do if a child with asthma is not benefiting sufficiently from inhaled corticosteroids.

This Cochrane review is available in full at www.mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD007949/frame.html

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October 5 2009