Association Between Pediatric Traumatic Brain Injury and Epilepsy at Later Ages in Finland - a Nationwide Register-based Cohort Study.

Abstract

To examine how pediatric traumatic brain injury (pTBI) correlated with incidence of epilepsy at later ages in Finland. A nationwide retrospective register-based cohort study from 1998 to 2018. The study group consisted of 71 969 pediatric (<18 years) patients hospitalized with TBI and a control group consisting of 64 856 pediatric patients with distal extremity fracture. Epilepsy diagnoses were gathered from the Finnish Social Insurance Institution. Kaplan-Meier (KM) and multivariable Cox regression models were conducted to analyze the probability of epilepsy with 95% confidence intervals (CI). Cumulative incidence rates (CIR) for the first 2 years were 0.5% in the pTBI group and 0.1% in the control group. The corresponding rates after 15 years of follow-up were 1.5% in the pTBI group and 0.7% in the control group. Due to proportional hazard (PH) violations, the study population was split to the first 2 years and in subgroup analysis 4 years. During the first 2 years of surveillance, the hazard ratio (HR) for the pTBI group was 4.38 (CI: 3.39-5.66). However, between years 2 and 20, the HR for the pTBI group was 2.02 (CI: 1.71-2.38). A total of 337 patients (0.47%) underwent neurosurgery and 36 (10.7%) patients subsequently developed epilepsy. The CIR for the first year after TBI were 4.5% (CI: 2.3-6.7%) in operatively managed patients and 0.3% (CI: 0.3-0.4%) in non-operatively managed patients. Corresponding figures after 15 years were 12.0% (CI: 8.2-15.8%) and 1.5% (CI: 1.4-1.6%). During the first 4 years of surveillance, the HR for the operative pTBI group was 14.37 (CI: 9.29-20.80) and 3.67 (CI: 1.63-8.22) between years 4 and 20. pTBI exposes patients to a higher risk for posttraumatic epilepsy (PTE) for many years after initial trauma. Children who undergo operative management for TBI have a high risk for epilepsy, and this risk was highest during the first 4 years after injury.