<p><strong>BACKGROUND: </strong>Use of intravenous magnesium (IVMg) for childhood asthma exacerbations has increased significantly in the last decade. Emergency department administration of IVMg has been shown to reduce asthma hospitalization, yet most children receiving IVMg in the emergency department are subsequently hospitalized. Our objective with the study was to examine hospital outcomes of children given IVMg for asthma exacerbations.</p>

<p><strong>METHODS: </strong>We conducted a retrospective cohort study using data from the Pediatric Health Information System. We used propensity score matching to compare children who received IVMg on the first day of hospitalization with those who did not. Primary outcomes were initiation and duration of noninvasive positive pressure ventilation. Secondary outcomes included mechanical ventilation (MV) initiation, duration of MV, length of stay, and subsequent tertiary medication use. Primary analysis was restricted to children admitted to nonintensive care inpatient units.</p>

<p><strong>RESULTS: </strong>Overall, 91 309 hospitalizations met inclusion criteria. IVMg was administered in 25 882 (28.4%) children. After propensity score matching, IVMg was not significantly associated with lower initiation (adjusted odds ratio 0.88; 95% confidence interval [CI] 0.74-1.05) or shorter duration of noninvasive positive pressure ventilation (rate ratio 0.94; 95% CI 0.87-1.02). Similarly, no significant associations were seen for MV initiation, MV duration, or length of stay. IVMg was associated with lower subsequent tertiary medication use (adjusted odds ratio 0.66; 95% CI 0.60-0.72). However, the association was lost when ipratropium was removed from the tertiary medication definition.</p>

<p><strong>CONCLUSIONS: </strong>IVMg administration was not significantly associated with improved hospital outcomes. Further study is needed to inform the optimal indications and timing of magnesium use during hospitalization.</p>