Incidence of Epilepsy after Neonatal Seizures: A Population-Based Study

Background: The incidence of childhood and adolescence epilepsy varies in different areas and over time. Published reports in the Italian pediatric population are few and there is no information on the incidence of epilepsy using the new clinical definition of the disease signed by the International League Against Epilepsy. An increased risk of epilepsy is reported in subjects who presented with neonatal seizures (NS), but few population-based studies are available that compare incidence and age at onset of epilepsy in children with and without NS. Objectives: Ascertain the incidence of epilepsy in children in the province of Parma by applying the new practical clinical definition of epilepsy, and compare incidence and age of epilepsy onset in children with and without previous NS. Methods: The study was carried out in the province of Parma, Emilia-Romagna Region, Northern Italy, using different data sources (clinical records and administrative data), and considered all the children born in the province of Parma between January 2002 and December 2014 and developing epilepsy by December 2016. We calculated the incidence of epilepsy in patients up to 14 years of age, incidence of epilepsy after NS and cumulative incidence of epilepsy at 1, 5, and 10 years' follow-up. To evaluate age at onset of epilepsy, we divided patients into 3 groups (epilepsy onset within 1 month, between 1 and 12 months, and after 1 year of life) and we compared age at onset of epilepsy between patients who had had previous NS and those who had not. Results: The incidence of epilepsy was 78.6/100,000 persons-years (boys 88.1/100,000, girls 68.6/100,000). The incidence of epilepsy after NS was 15.2% (8.2% for male, 23.5% for female; 16.3% in born at term, 14.3% in pre-term). The incidence of epilepsy at 1, 5, and 10 years' follow-up was higher in patients with previous NS than in others. The age at onset of epilepsy was significantly different in the 2 groups, and was younger in those with history of NS: mean age at onset was 10.5 months in those with NS and of 61.8 months in the others. Conclusions: The incidence rate of epilepsy in the Parma district was higher than that reported in other Italian areas studied, probably due to the different methodology used and the application of the most recent definition of epilepsy. Children with NS were at higher risk of epilepsy and develop the disease at a younger age.