<p>Intravenous (IV) magnesium is used as an adjunct therapy in management of status asthmaticus with a goal of reducing intubation rate. A recent review suggests that IV magnesium use in status asthmaticus reduces admission rates. This is contrary to the observation of practicing emergency room physicians. The goal of this study was to assess trends in IV magnesium use for status asthmaticus in US children's hospitals over 8 years through a retrospective analysis of children younger than 18 years using the Pediatric Health Information System database. Outcomes were IV magnesium use, inpatient and intensive care unit admission rate, geometric mean length of stay, and 7-day all-cause readmission rate. IV magnesium use for asthma hospitalization more than doubled over 8 years (17% vs. 36%; P &lt; .001). Yearly trends were not significantly associated with hospital or intensive care unit admission rate or 7-day all-cause readmissions, although length of stay was reduced (P &lt; .001).</p>

<p><strong>BACKGROUND AND OBJECTIVES: </strong>The Pediatric Respiratory Illness Measurement System (PRIMES) generates condition-specific composite quality scores for asthma, bronchiolitis, croup, and pneumonia in hospital-based settings. We sought to determine if higher PRIMES composite scores are associated with improved health-related quality of life, decreased length of stay (LOS), and decreased reuse.</p>

<p><strong>METHODS: </strong>We conducted a prospective cohort study of 2334 children in 5 children's hospitals between July 2014 and June 2016. Surveys administered on admission and 2 to 6 weeks postdischarge assessed the Pediatric Quality of Life Inventory (PedsQL). Using medical records data, 3 PRIMES scores were calculated (0-100 scale; higher scores = improved adherence) for each condition: an overall composite (including all quality indicators for the condition), an overuse composite (including only indicators for care that should not be provided [eg, chest radiographs for bronchiolitis]), and an underuse composite (including only indicators for care that should be provided [eg, dexamethasone for croup]). Multivariable models assessed relationships between PRIMES composite scores and (1) PedsQL improvement, (2) LOS, and (3) 30-day reuse.</p>

<p><strong>RESULTS: </strong>For every 10-point increase in PRIMES overuse composite scores, LOS decreased by 8.8 hours (95% confidence interval [CI] -11.6 to -6.1) for bronchiolitis, 3.1 hours (95% CI -5.5 to -1.0) for asthma, and 2.0 hours (95% CI -3.9 to -0.1) for croup. Bronchiolitis overall composite scores were also associated with shorter LOS. PRIMES composites were not associated with PedsQL improvement or reuse.</p>

<p><strong>CONCLUSIONS: </strong>Better performance on some PRIMES condition-specific composite measures is associated with decreased LOS, with scores on overuse quality indicators being a primary driver of this relationship.</p>