Epidemiology of Treated Epilepsy in New Zealand Children: A Focus on Ethnicity.

Objective: To determine the period prevalence and incidence of treated epilepsy in a New Zealand (NZ) pediatric cohort with a focus on ethnicity and socioeconomic status. Methods: This was a retrospective cohort study. The NZ Pharmaceutical Collection database was searched for individuals (≤18 years) dispensed an antiseizure medication (ASM) in 2015 from areas capturing 48% of the NZ pediatric population. Medical records of identified cases were reviewed to ascertain the indication for the ASM prescription. Population data was derived from the NZ 2013 Census. Results: 3557 ASMs were prescribed during 2015 in 2594 children, of whom 1717 (66%) children had epilepsy. An indication for prescription was ascertained for 3332/3557 (94%) of ASMs. The period prevalence of treated epilepsy was 3.4 per 1000 children. Children in the most deprived areas had 1.9 times the rate of treated epilepsy (95% CI 1.6-2.2) than those from the least deprived areas. Prevalence was similar for most ethnic groups (European/Other - 3.7, 95% CI 3.4-3.9; Pacific Peoples - 3.6, 95% CI 3.2-4.1; Māori - 3.4, 95% CI 3.1-3.8) apart from Asians, who had a lower prevalence of 2.3 per 1000 (95% CI 2.0-2.6). However, when adjusted for socioeconomic deprivation, the prevalence of epilepsy was highest in Europeans and similar in Māori, Pacific and Asian children. Conclusions: This is the largest pediatric epidemiology epilepsy study where diagnosis of epilepsy was confirmed by case review. This is the first study to provide epidemiological information for pediatric epilepsy in Māori and Pacific children.