Impact of dexamethasone on transplant-related mortality in pediatric patients: a multi-site, propensity score-weighted, retrospective assessment.

Dexamethasone use during hematopoietic cell transplant (HCT) conditioning varies between pediatric centers. This study aimed to estimate the difference in 1-year treatment-related mortality (TRM) between patients who did or did not receive dexamethasone during HCT conditioning. Secondary objectives were to estimate the difference between dexamethasone-exposed and dexamethasone-unexposed groups in 1-year event-free survival (EFS), time to neutrophil engraftment, acute graft-versus-host disease (aGVHD), and invasive fungal disease (IFD) at day + 100. This was a seven-site, international, retrospective cohort study. Patients < 18 years old undergoing their first allogeneic or autologous myeloablative HCT for hematologic malignancy or aplastic anemia between January 1, 2012, and July 31, 2017, were included. To control for potential confounders, propensity score weighting was used to calculate the standardized mean difference for all endpoints. Among 242 patients, 140 received dexamethasone during HCT conditioning and 102 did not. TRM was unaffected by dexamethasone exposure (1.7%; 95% CI - 7.4, 10.2%). Between-group differences in secondary outcomes were small. However, dexamethasone exposure significantly increased possible, probable, and proven IFD incidence (9.0%, 95% CI 0.8, 17.3%). TRM is not increased in pediatric patients who receive dexamethasone during HCT conditioning. Clinicians should consider potential IFD risk when selecting chemotherapy-induced vomiting prophylaxis for pediatric HCT patients.