Background and Objective:Background and Objective: Febrile neutropenia (FN) is a potentially life-threatening condition that may develop in cancer patients treated with myelosuppressive chemotherapy and result in considerable costs. This study was designed to estimate US healthcare utilization and costs in those experiencing FN by location of care, tumour type and mortality. Abstract: Methods:Methods: Cancer patients who received chemotherapy between 2001 and 2006 were identified from the HealthCore Integrated Research Database, a longitudinal claims database with enrolment, medical, prescription and mortality information covering 12 health plans and more than 20 million US patients. Patients who experienced FN were prospectively matched using propensity score methods within each tumour type of interest (non-Hodgkin's lymphoma, breast, lung, colorectal and ovarian cancer) to those not experiencing FN. Health resource utilization was compared per patient per month for unique prescriptions and visits (inpatient and outpatient) over the length of follow-up. Healthcare total paid costs adjusted to 2009 US dollars per patient per month were examined by FN group (FN vs non-FN, FN died vs FN survived), by source of care (physician office visit, outpatient services, hospitalization and prescriptions) and by tumour type. The number of unique FN-related encounters (inpatient and outpatient) and the number of patients experiencing at least one FN-related encounter were examined. The costs per encounter were tabulated. FN encounters differ from FN episodes in that a single FN episode may include multiple FN encounters (i.e. a patient is seen multiple times [encounters] for treatment of a single FN event [episode]). Abstract: Results:Results: A total of 5990 patients each were successfully matched between the FN and non-FN (control) groups. Health resource utilization was generally higher in those with FN than in controls. FN patients incurred greater costs (mean ± SD: $US9628 ± 12 517 per patient-month) than non-FN patients ($US8478 ± 12 978). Chemotherapy comprised the majority of costs for both FN (33.5%) and non-FN (40.6%) patients. The largest cost difference by categorical source of care was for hospitalization (p < 0.001). FN patients who died had the highest mean total costs compared with FN surviving patients ($US21 214 ± 25 596 per patient-month vs $US8227 ± 8850, respectively). Follow-up time for those surviving was, on average, 6.6 months longer. Hospitalization accounted for 53.1% of costs in those experiencing mortality with FN, while chemotherapy accounted for the majority of costs (37.1%) in surviving FN patients. A total of 6574 patients with at least one FN encounter experienced a total of 55 726 unique FN-related encounters, 90% of which were outpatient in nature. The majority of FN-related encounters (79%) occurred during the first chemotherapy course. The average costs for FN encounters were highest for inpatient encounters, $US22 086 ± 43 407, compared with $US985 ± 1677 for outpatient encounters. Abstract: Conclusions:Conclusions: The occurrence of FN in cancer patients receiving chemotherapy results in greater healthcare resource utilization and costs, with FN patients who die accounting for the greatest healthcare costs. Most FN patients experience at least one outpatient FN encounter, and the total cost of treatment for FN continues to be high.