<p>Although inferior outcomes of children with Down syndrome (DS) and acute lymphoid leukaemia (ALL) are established, national supportive care patterns for these patients are unknown. A validated retrospective cohort of paediatric patients diagnosed with ALL from 1999 to 2011 was assembled from the US Pediatric Health Information System (PHIS) database to examine organ toxicity, sepsis, and resource utilization in children with and without DS. Among 10699 ALL patients, 298 had DS-ALL (2·8%). In a multivariate model, DS was associated with increased risk of cardiovascular (odds ratio [OR] 2·0, 95% confidence interval [CI] 1·6-2·7), respiratory (OR 2·1, 95% CI: 1·6-2·9), neurologic (OR 3·4, 95% CI 1·9-6·2), and hepatic (OR 1·4, 95% CI 1·0-1·9) dysfunction and sepsis (OR 1·8, 95% CI: 1·4-2·4). Children with DS-ALL used significantly more respiratory support, insulin, and anti-infectives, including broad-spectrum Gram-positive agents, quinolones, and azoles. They used significantly fewer analgesics and antiemetics compared to non-DS-ALL children. Ultimately, this study confirms the increased risk of infectious and end-organ toxicity in children with DS-ALL and quantifies important differences in resource utilization between children with DS and non-DS ALL. These findings highlight the importance of investigating the impact of these care variations and developing specific supportive care guidelines for this population.</p>

<p><strong>IMPORTANCE: </strong>In adult patients with leukemia, weekend admission is associated with increased inpatient mortality. It is unknown whether weekend diagnostic admissions in pediatric patients with leukemia demonstrate similar adverse outcomes.</p>

<p><strong>OBJECTIVE: </strong>To estimate adverse clinical outcomes associated with weekend admission in the first hospitalization of pediatric patients with newly diagnosed leukemia.</p>

<p><strong>DESIGN, SETTING, AND PARTICIPANTS: </strong>This retrospective cohort study from 1999 to 2011 featured index hospital admissions identified from the Pediatric Health Information System database. Participants were children with newly diagnosed acute lymphoid leukemia or acute myeloid leukemia.</p>

<p><strong>EXPOSURES: </strong>Weekend (Saturday and Sunday) or weekday index admission.</p>

<p><strong>MAIN OUTCOMES AND MEASURES: </strong>Inpatient mortality, length of inpatient stay, time to chemotherapy, and organ-system failure in index admission.</p>

<p><strong>RESULTS: </strong>A total of 10 720 patients with acute lymphoid leukemia and 1323 patients with acute myeloid leukemia were identified; 2009 patients (16.7%) were admitted on the weekend. While the total daily number of patients receiving intensive care unit-level care was constant regardless of the day of admission, these patients represented a larger percentage of total admissions on weekends. In adjusted analyses, patients admitted on the weekend did not have an increased rate of mortality during the first admission (odds ratio, 1.0; 95% CI, 0.8-1.6). Patients whose initial admission for leukemia occurred during a weekend had a significantly increased length of stay (1.4-day increase; 95% CI, 0.7-2.1), time to initiation of chemotherapy (0.36-day increase; 95% CI, 0.3-0.5), and risk for respiratory failure (odds ratio, 1.5; 95% CI, 1.2-1.7) after adjusting for demographics, severity of illness, and hospital-level factors.</p>

<p><strong>CONCLUSIONS AND RELEVANCE: </strong>While pediatric patients with newly diagnosed leukemia admitted on weekends do not have higher mortality rates, they have a prolonged length of stay, increased time to chemotherapy, and higher risk for respiratory failure. Patients who are severely ill at presentation represent a higher proportion of weekend index admissions. Optimizing weekend resources by increasing staffing and access to diagnostic and therapeutic resources may help to reduce hospital length of stay across all weekend admissions and may also ensure the availability of comprehensive care for those weekend admissions with higher acuity.</p>