Primary objective: The objective was to estimate and compare the hazards of repetitive traumatic brain injury (RTBI) events as a function of the index TBI severity, in a cohort of TBI hospital discharges include in the South Carolina Traumatic Brain Injury Follow-up Registry.

Research design: Retrospective cohort.

Methods and procedures: There were 4357 persons with TBI who were followed from the index hospital discharge through 31 December 2005 for RTBI events through the statewide hospital discharge (HD) and emergency department (ED) records. Prentice, Williams, Peterson total time/conditional probability model (PWP-CP) for recurrent events survival analysis was used to assess RTBI as a function of index TBI severity.

Main outcomes and results: Index TBI severity approached significance in its relationship with RTBI, with persons with a severe index TBI experiencing events at a higher rate than those with a mild/moderate index TBI. Among the other covariates evaluated, epilepsy/seizure disorder, race, gender, payer status, cause of injury and having a prior history of TBI were associated with RTBI.

Conclusions: While TBI severity approached significance with RTBI, other variables, such as epilepsy/seizure disorder, seem to have a more significant relationship with RTBI.