To examine the incidence, treatment, and consequences of febrile neutropenia across inpatient and outpatient care settings.

Data were obtained from Humedica's National Electronic Health Record-Derived Longitudinal Patient-Level Database (2007–2010). The study population included adult patients who received myelosuppressive chemotherapy for a solid tumor or non-Hodgkin’s lymphoma. For each patient, each chemotherapy regimen course and each cycle within each regimen course was characterized. Febrile neutropenia episodes were identified on a cycle-specific basis based on any of the following: (1) absolute neutrophil count <1.0 × 10⁹/L and evidence of infection or fever; (2) inpatient diagnosis of neutropenia, fever, or infection; (3) outpatient diagnosis of neutropenia and non-prophylactic antimicrobial use; or (4) mention of febrile neutropenia in physician notes. Febrile neutropenia episodes were categorized as inpatient or outpatient based on the initial setting of care (i.e. acute-care inpatient facility vs. ambulatory care facility). Febrile neutropenia consequences included hospital length of stay and mortality (inpatient cases only), as well as number of febrile neutropenia-related outpatient encounters.

Among the 2131 patients in this study, 401 experienced a total of 458 febrile neutropenia episodes. Risk of febrile neutropenia during the chemotherapy regimen course was 16.8% (95% CI: 15.3, 18.4). In cycle 1 alone, risk of febrile neutropenia was 8.1% (7.1, 9.3). Most febrile neutropenia episodes (83.2%) were initially treated in the inpatient setting; the hospital mortality rate was 8.1% (5.8, 11.1), and mean hospital length of stay was 8.4 days (7.7, 9.1). Among febrile neutropenia episodes initially treated in the outpatient setting (16.8%), the mean number of outpatient management encounters was 2.6 (2.1, 3.1), most of which were in the physician’s office (69.2%) or emergency department (26.9%).

Febrile neutropenia remains a common occurrence among patients receiving myelosuppressive chemotherapy and typically results in extended hospitalization and, for many patients, death. A minority of patients are, however, treated exclusively on an outpatient basis.