US estimates of hospitalized children with severe traumatic brain injury: implications for clinical trials.

OBJECTIVES: To estimate sample sizes available for clinical trials of severe traumatic brain injury (TBI) in children, we described the patient demographics and hospital characteristics associated with children hospitalized with severe TBI in the United States.
METHODS: We analyzed the 2006 Kids' Inpatient Database. Severe TBI hospitalizations were defined as children discharged with TBI who required mechanical ventilation or intubation. Types of high-volume severe TBI hospitals were categorized based on the numbers of discharged patients with severe TBI in 2006. National estimates of demographics and hospital characteristics were calculated for pediatric severe TBI. Simulation analyses were performed to assess the potential number of severe TBI cases from randomly selected hospitals for inclusion in future clinical trials.
RESULTS: The majority of children with severe TBI were discharged from either a children's unit in general hospitals (41%) or a nonchildren's hospital (34%). Less than 5% of all hospitals were high-volume TBI hospitals, which discharged >78% of severe TBI cases and were more likely to be a children's unit in a general hospital or a children's hospital. Simulation analyses indicate that there is a saturation point after which the benefit of adding additional recruitment sites decreases significantly.
CONCLUSIONS: Children with severe TBI are infrequent at any one hospital in the United States, and few hospitals treat large numbers of children with severe TBI. To effectively plan trials of therapies for severe TBI, much attention has to be paid to selecting the right types of centers to maximize enrollment efficiency.