Abstract 18284: Incidence of Epilepsy is Elevated in Children and Young Adults With Congenital Heart Defects Compared With the General Population: A Nationwide Cohort Study

Perioperative seizures related to surgery for congenital heart defects (CHD) are well described; however, few data exist on the long-term risk of epilepsy in patients with CHD. We aimed to estimate the incidence of epilepsy in children and young adults with CHD compared with the general population. Methods: Utilizing data from the Danish National Registry of Patients (DNRP) we identified all patients diagnosed with CHD before the age of 15 years between 1980 and 2010 who were born during the same period. The DNRP is a nationwide hospital discharge registry covering all Danish hospitals. Previously validated methodology using the DNRP was applied to measure the outcome, epilepsy, as well as presence of extra cardiac defects (ECD) and/or syndromes. We used the Danish Medical Birth Registry to identify preterm birth (gestational age<37 weeks). For each CHD subject, we identified 10 controls from the general population using the Danish Civil Registration System, matched by sex and birth year. A unique personal identifier assigned at birth and used in all Danish public registries enabled virtually complete follow up for migration, death, or epilepsy until January 1, 2013. We computed cumulative incidences and hazard ratios (HR) (split at 5 years of age to obtain proportional hazards) of time from CHD diagnosis (index date for controls) to epilepsy. Results: We identified 14,665 CHD subjects with a median age at diagnosis of 2 (IQR 19) months. By 15 years of age, the cumulative incidence of epilepsy was 4% among CHD subjects. The HR of epilepsy among CHD subjects compared with the control cohort was 3.7 (95% CI: 3.2-4.3) below 5 years of age, and 2.4 (95% CI: 2.1-2.7) from 5 to 33 years of age. In the older age group, HR for patients with severe CHD was 2.8 (95% CI: 2.3-3.5), and for mild and moderate CHD was 2.2 (95% CI: 1.8-2.6). After exclusion of all subjects with ECDs and/or syndromes and preterm birth, corresponding HRs were 2.2 (95% CI: 1.6-3.0) and 1.7 (95% CI: 1.3-2.2), respectively. Conclusion: The epilepsy risk was markedly increased in CHD subjects compared with the age and gender matched controls. These findings add evidence to support the importance of developing neuro-protective measures and potentially long-term epilepsy surveillance strategies in the CHD population.