Early and late posttraumatic seizures following traumatic brain injury: A five-year follow-up survival study

BACKGROUND: The main objective of this study was to determine the incidence, time to event, and risk factors for posttraumatic seizures (PTS) following traumatic brain injury (TBI) in a five-year follow-up survival design. MATERIALS AND METHODS: In a cohort study, between September 2008 and October 2013, 411 traumatic brain injury patients referring to the Emergency Units (EUs) of the Isfahan University Hospitals, who met the inclusion criteria, entered the study. Follow-up evaluations were conducted by telephone conversation or clinical examination, if needed. The patients were followed for up to five years after TBI or until a first seizure event if it occurred prior to the five-year anniversary. The survival rate data were collected and measured for all patients under follow-up. Survival analysis on PTS and its related predictors was done using the Kaplan-Meier curves and the Cox proportional hazards regression. All analyses were done using STATA and SPSS statistical software, and P-values smaller than 0.05 were considered to be statistically significant. RESULTS: The median duration of follow-up was 36 months (Interquartile range: 23-50). A significantly greater number of first seizures occurred in the first year after injury than all other years (57.7%). The overall incidence of posttraumatic seizures, in this study population, was 6.33% (95% CI: 3.96-8.69). Among the participants, the incidence rates for early and late posttraumatic seizures were 1.95 and 4.38%, respectively. The result of the Cox regression analysis showed that the Glasgow Coma Scale (GCS) score and trauma severity were associated with PTS. CONCLUSION: All in all, the present study highlighted the role of the trauma severity and GCS as effective factors in the incidence of seizure in patients with TBI. Particular care is advised for patients with these risk factors during the primary handling in the Emergency Units.