A meta-analysis on intravenous magnesium sulphate for treating acute asthma

Aim: To evaluate the effectiveness of intravenous magnesium sulphate in the treatment of acute asthmatic attacks in children by meta-analysis. Methods: A systematic and comprehensive search of the literature was performed to identify controlled clinical trials of magnesium sulphate in paediatric acute asthma which evaluated outcomes of hospitalisation or short term pulmonary function tests or symptom scores. Unpublished data were searched by personal contacts with authors and specialists. Two reviewers independently assessed trial qualities and synthesised data. Heterogeneity among studies was evaluated by the Cochrane Q test. Outcome data were pooled by random or fixed effect models depending on presence or absence of heterogeneity. Results: Five randomised placebo controlled trials involving a total of 182 patients were identified. They compared intravenous magnesium sulphate to placebo in treating paediatric patients with moderate to severe asthmatic attacks in the emergency department, with co-therapies of inhaled beta(2) agonists and systemic steroids. The studies were of high quality with results judged to be valid. Four studies showed that magnesium sulphate was effective, while one study found it ineffective. There was no significant heterogeneity in the primary outcome of hospitalisation. In the fixed effect model, magnesium sulphate is effective in preventing hospitalisation (OR 0.290, 95% CI 0.143 to 0.589). The number needed to treat is 4 ( 95% CI 3 to 8). Secondary outcomes of short term pulmonary function tests and clinical symptom scores also showed significant improvement. Conclusion: Intravenous magnesium sulphate probably provides additional benefit in moderate to severe acute asthma in children treated with bronchodilators and steroids.