<p><strong>BACKGROUND AND OBJECTIVES: </strong>Patient complexity at US children's hospitals is increasing. Hospitals experience concurrent pressure to reduce length of stay (LOS) and readmissions, yet little is known about how these common measures of resource use and quality have changed over time. Our aim was to examine temporal trends in medical complexity, hospital LOS, and readmissions across a sample of US children's hospitals.</p>

<p><strong>METHODS: </strong>Retrospective cohort study of hospitalized patients from 42 children's hospitals in the Pediatric Health Information System from 2013 to 2017. After excluding deaths, healthy newborns, obstetric care, and low volume service lines, we analyzed trends in medical complexity, LOS, and 14-day all-cause readmissions using generalized linear mixed effects models, adjusting for changes in patient factors and case-mix.</p>

<p><strong>RESULTS: </strong>Between 2013 and 2017, a total of 3 355 815 discharges were included. Over time, the mean case-mix index and the proportion of hospitalized patients with complex chronic conditions or receiving intensive care increased ( &lt; .001 for all). In adjusted analyses, mean LOS declined 3% (61.1 hours versus 59.3 hours from 2013 to 2017, &lt; .001), whereas 14-day readmissions were unchanged (7.0% vs 6.9%; = .03). Reductions in adjusted LOS were noted in both medical and surgical service lines (3.6% and 2.0% decline, respectively; &lt; .001).</p>

<p><strong>CONCLUSIONS: </strong>Across US children's hospitals, adjusted LOS declined whereas readmissions remained stable, suggesting that children's hospitals are providing more efficient care for an increasingly complex patient population.</p>

<p><strong>OBJECTIVES: </strong>Suicide ideation (SI) and suicide attempts (SAs) have been reported as increasing among US children over the last decade. We examined trends in emergency and inpatient encounters for SI and SA at US children's hospitals from 2008 to 2015.</p>

<p><strong>METHODS: </strong>We used retrospective analysis of administrative billing data from the Pediatric Health Information System database.</p>

<p><strong>RESULTS: </strong>There were 115 856 SI and SA encounters during the study period. Annual percentage of all visits for SI and SA almost doubled, increasing from 0.66% in 2008 to 1.82% in 2015 (average annual increase 0.16 percentage points [95% confidence intervals (CIs) 0.15 to 0.17]). Significant increases were noted in all age groups but were higher in adolescents 15 to 17 years old (average annual increase 0.27 percentage points [95% CI 0.23 to 0.30]) and adolescents 12 to 14 years old (average annual increase 0.25 percentage points [95% CI 0.21 to 0.27]). Increases were noted in girls (average annual increase 0.14 percentage points [95% CI 0.13 to 0.15]) and boys (average annual increase 0.10 percentage points [95% CI 0.09 to 0.11]), but were higher for girls. Seasonal variation was also observed, with the lowest percentage of cases occurring during the summer and the highest during spring and fall.</p>

<p><strong>CONCLUSIONS: </strong>Encounters for SI and SA at US children's hospitals increased steadily from 2008 to 2015 and accounted for an increasing percentage of all hospital encounters. Increases were noted across all age groups, with consistent seasonal patterns that persisted over the study period. The growing impact of pediatric mental health disorders has important implications for children's hospitals and health care delivery systems.</p>