Independent role of neonatal seizures in subsequent neurological outcomes: a population-based study.

Aim This population-based study aimed to estimate the impact of neonatal seizures on subsequent neurological outcomes, regardless of underlying etiology. Method We performed a retrospective cohort study (1st January 2009-31st December 2014), using a USA nationwide claims database. Newborn infants enrolled in 2009 were followed for up to 6 years. Neonatal seizures were identified by combining the International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis code of 779.0 (convulsions in newborn), procedure codes of electroencephalogram and brain imaging, and antiepileptic drugs claims. Cox regression models were built to estimate the independent impact of neonatal seizures on developing epilepsy, intellectual disability, psychiatric/behavioral disorders, and headache. Results Out of 490 071 newborn infants (251 850 males [51.4%], 238 221 females [48.6%]), 800 neonatal seizure cases were identified. After controlling for sex, birthweight, preterm birth status, and underlying etiology, neonates with seizures were more likely to have epilepsy (hazard ratio=32.7; 95% confidence interval [CI]=27.7-38.7; p<0.001), intellectual disability (hazard ratio=2.0; 95% CI=1.8-2.3; p<0.001), and headache (hazard ratio=1.6; 95% CI=1.1-2.2; p=0.013) than those without seizures. Interpretation Observed covariates being equal, seizures in neonates appeared to play a significant role in developing epilepsy, intellectual disability, and headache. The findings showed a detrimental impact of the event in the very early life on neurological outcomes in later life.