<p><strong>IMPORTANCE: </strong>AlloHCT may be associated with significant morbidity and mortality that result in increased healthcare utilization. To date, no multi-center comparative cost analyses have been performed specifically evaluating alloHCT in children with acute leukemia.</p>
<p><strong>OBJECTIVES: </strong>To describe the relationship between survival and healthcare utilization while investigating the hypothesis that matched sibling donor (MSD) alloHCT has significantly lower inpatient healthcare utilization compared to unrelated donor (URD) and that among URD, umbilical cord blood transplants (UCB) will have higher initial but lower long-term utilization.</p>
<p><strong>DESIGN: </strong>Retrospective cohort study Setting: Clinical and transplant outcomes data from the Center for International Blood and Marrow Transplant Research (CIBMTR) were merged with inpatient cost data from the Pediatric Health Information System (PHIS) database using a probabilistic merge methodology.</p>
<p><strong>PARTICIPANTS: </strong>The merged dataset contained U.S. patients age 1-21 years who received alloHCT for acute leukemia from 2004-2011 with comprehensive CIBMTR data at a PHIS hospital.</p>
<p><strong>EXPOSURE: </strong>AlloHCT analyzed by donor type with specific analysis of utilization and costs using PHIS claims data.</p>
<p><strong>MAIN OUTCOME: </strong>The primary outcomes of overall survival (OS), leukemia free survival (LFS), and inpatient costs were evaluated using Kaplan-Meier curves, Cox, and Poisson models.</p>
<p><strong>RESULTS: </strong>632 patients were identified in both CIBMTR and PHIS. 5-year LFS was 60% for MSD, 47% for well-matched matched unrelated donor bone marrow (MUD), 48% for mismatched unrelated donor, and 45% for UCB (p=0.09). Total adjusted costs were significantly lower for MSD versus MUD by day 100 (adjusted cost ratio (ACR) 0.73, CI 0.62-0.86, p<0.001), and higher for UCB versus MUD (ACR 1.27, CI 1.11-1.45, p<0.001). By 2yrs, total adjusted costs remained significantly lower for MSD when compared to MUD (ACR 0.67, CI 0.56-0.81, p<0.001) and higher for UCB compared to MUD (ACR 1.25, 95% CI 1.02-1.52, p=0.0280).</p>
<p><strong>CONCLUSIONS: </strong>UCB and MUD alloHCT provide similar survival outcomes; however, MUD alloHCT has a significant advantage in cost by day 100 and 2 years. Ongoing research is needed to determine if the cost difference among URD alloHCT remains significant with a larger sample size and/or beyond the 2 years following alloHCT.</p>
<p><strong>BACKGROUND: </strong>BK polyomavirus (BKPyV) is associated with symptomatic hemorrhagic cystitis after hematopoietic cell transplantation (HCT). Little is known about the host immune response, effectiveness of antiviral treatment, or impact of asymptomatic replication on long-term kidney function.</p>
<p><strong>METHODS: </strong>In children and young adults undergoing allogeneic HCT, we quantified BKPyV viruria and viremia (pre-HCT and at months 1-4, 8, 12, and 24 post-HCT) and tested associations of peak viremia ≥10 000 or viruria ≥109 copies/mL with estimated kidney function (eGFR) and overall survival for two years post-transplant. We examined factors associated with viral clearance by month 4 including BKPyV-specific T cells by enzyme-linked immune absorbent spot (ELISPOT) at month 3 and cidofovir use.</p>
<p><strong>RESULTS: </strong>We prospectively enrolled 193 participants (median age 10 years). 18% had viremia ≥10 000 copies/mL, and 45% had viruria ≥109 copies/mL in the first three months post-HCT. Among the 147 participants without cystitis (asymptomatic), 58 (40%) had any viremia. In the entire cohort and asymptomatic subset, viremia ≥10 000 copies/mL was associated with a lower creatinine/cystatin C eGFR two years post-HCT. Viremia ≥10 000 copies/mL was associated with a higher risk of death (adjusted hazard ratio, 2.2; 95% confidence interval, 1.1-4.2). Clearing viremia was associated with detectable BKPyV-specific T cells and viremia <10 000 copies/mL, but not cidofovir exposure.</p>
<p><strong>CONCLUSIONS: </strong>Screening for BKPyV viremia after HCT identifies asymptomatic patients at risk for kidney disease and reduced survival. These data suggest potential changes to clinical practice, including prospective monitoring for BKPyV viremia to test virus-specific T cells to prevent or treat BKPyV replication.</p>