Intravenous magnesium not beneficial for children with acute asthma exacerbations
Published: December 12, 2021
Expert guidelines recommend consideration of intravenous magnesium (IV-Mg) for children with moderate or severe acute asthma exacerbations who have an incomplete response to systemic corticosteroids (CCS) and inhaled albuterol. Although use of this treatment is increasing, there is limited data whether it improves outcomes. A Cochrane systematic review concluded that the quality of randomized clinical trials of IV-Mg for exacerbations was poor. And though recent research indicates that IV-Mg is associated with increased hospitalizations without improved in-hospital outcomes such as decreased length of stay, these studies are limited by confounding by indication in which factors that may influence the decision of which patients to treat with IV-Mg may also affect treatment outcome. For example, a clinician with a low threshold to treat with IV-Mg may also be more likely to admit a patient to the intensive care unit (ICU).
In original research recently published in The Journal of Allergy and Clinical Immunology: In Practice, Arnold et al analyzed data from a large, prospective cohort of children aged 5 – 17 years with moderate and severe asthma exacerbations to examine whether IV-Mg treatment was associated with improvement in clinically relevant outcomes. The primary outcome was change of severity 2 hours after treatment, measured using the validated Acute Asthma Intensity Research Score (AAIRS), scored 0 – 16 points with 16 most severe. Secondary outcomes included hospitalization rate and time to spacing inhaled albuterol (a bronchodilator) to 4 hours or more (a measure of exacerbation resolution) in those who were hospitalized.
The propensity score (PS) method was applied to limit confounding by indication in examining the association of IV-Mg with these outcomes. For the primary outcome of interest, change of the AAIRS, the PS was used as a variable in 4 different multivariable regression models to predict this outcome. To examine hospitalization rate, a similar multivariable model was used. A “time-to-event” method of multivariable regression (Cox proportional hazards) was used to examine time to inhaled albuterol of 4 hours or more (an accepted metric of exacerbation resolution). All regression models were adjusted for variables, including the PS, that might confound associations of IV-Mg with the outcomes of interest.
Among 301 children who met study inclusion criteria, median age was 8.1 years, 57% were Black, 67% were male, and 28% received IV-Mg. The PS-adjusted multivariable linear regression models indicated that treatment with IV-Mg was actually associated with a 1-point worsening of the AAIRS after 2 hours. In addition, those receiving IV-Mg had 5.8-fold greater odds of hospitalization. Among those hospitalized there was no difference in time to albuterol of every 4 hours or more.
In children with moderate to severe asthma exacerbations, this study suggests that treatment with IV-Mg is associated with increased exacerbation severity after two hours, a nearly 6-fold increased odds of hospitalization, and no change in the rate of exacerbation resolution among those hospitalized. Until randomized controlled trials are conducted that are powered to examine these and other important outcomes, there is insufficient evidence to support IV-Mg for moderate and severe acute asthma exacerbations in children.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.
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