1550. Pediatric Febrile Neutropenia: Does Depth and Duration of Neutropenia at Presentation Predict Outcomes?

BACKGROUND: The 2010 Infectious Diseases Society of America (IDSA) guidelines define febrile neutropenia (FN) patients as high risk if they have profound neutropenia [ANC (absolute neutrophil count) ≤100 cells/μL] anticipated to last >7 days. Formal studies to clearly evaluate the significance of the depth of neutropenia are lacking. METHODS: A retrospective cohort study of all pediatric oncology patients presenting with FN between July 2009–December 2016 was performed to evaluate if the depth and duration of neutropenia prior to presentation was correlated with blood stream infection (BSI), invasive fungal disease (IFD), pediatric intensive care unit (PICU) admission or length of stay (LOS). Patients were categorized into three groups based on ANC at time of presentation: <100, 100–500, and >500 cells/mL with decreasing ANC over the subsequent 48 hours. Durations of neutropenia prior to presentation were also assessed. RESULTS: A total of 585 FN episodes (FNEs) were identified in 265 patients presenting with 411(70%) ANC <100, 119(20%) ANC 100–500 and 55 (10%) ANC >500 with subsequent decline over 48 hours. Underlying diagnoses included ALL (32%), AML (29%), lymphoma (16%), neuroblastoma (16%) and other solid tumors (9%). In group ANC >500; 70% (39/55) of received chemotherapy within 2 weeks of presentation and 35% were s/p SCT. Rates of IFD and BSI were higher in the group with ANC > 500 with decline in 48 hours compared with ANC < 100 (OR = 5.9, P = 0.03) and ANC 100–500 (OR = 5.6, P = 0.034). Patients with ANC>500 cells/mL were significantly more likely to be admitted to the PICU (OR = 5.00, P = 0.017) and had an increased LOS (hazard ratio = 0.55, P = 0.002) when compared with the other two groups. No difference in PICU admission or mortality was found when patients presenting with fevers and ANC < 100 were compared with ANC 100–500. Neutropenia ≥7 days prior to FN was an independent risk factor for BSI (OR = 2.8, P = 0.001). CONCLUSION: Pediatric patients presenting with febrile neutropenia and initial ANC >500 cells/mL with decine over 48 hours had a higher incidence of BSI, IFD, PICU admissions Clinicians should not be reassured when patients present with fever and initial ANC >500 cells/mL after undergoing recent chemotherapy if continued decline is expected. More work needs to be done to evaluate for risk factors at the time of presentation with FN to guide clinical care. DISCLOSURES: All authors: No reported disclosures.