Effect of intravenous magnesium sulfate on mortality in patients with severe acute asthma

Intravenous magnesium sulfate is used as adjunctive therapy for severe asthma exacerbations. However, previous randomized controlled trials of the administration of intravenous magnesium sulfate for asthma exacerbations have shown mixed results, and no study has evaluated its effect on mortality in patients with life-threatening asthma. The objective of this study was to investigate the association between intravenous magnesium sulfate administration and mortality in patients with severe asthma.

Patients with severe asthma requiring intravenous corticosteroids and oxygenation were selected using the Japanese Diagnosis Procedure Combination inpatient database. One-to-one propensity score matching was performed between patients having received or not intravenous magnesium sulfate. Primary outcomes were 7-, 14- and 28-day mortalities. Secondary outcomes were total dose of intravenous corticosteroids during hospitalization, duration of mechanical ventilation and length of stay.

Among 14,122 eligible patients, 619 received intravenous magnesium sulfate. Propensity score matching created a matched cohort of 599 pairs with and without intravenous magnesium sulfate. There were no significant differences between patients with and without intravenous magnesium sulfate in terms of 28-day mortality (1.3% vs 1.8%, P = 0.488), median total dose of intravenous corticosteroids (2400 mg vs 2400 mg, P = 0.580), median duration of mechanical ventilation (1 day vs 1 day, P = 0.118) and median length of stay (16 days vs 13 days, P = 0.640).

This study found no significant benefit of intravenous magnesium sulfate use in terms of mortality in patients with severe acute asthma.