CHARACTERIZING THE EPIDEMIOLOGY OF EPILEPSY IN SASKATCHEWAN, CANADA

Abstract

Background and objectives: There are few studies of the prevalence of epilepsy in Canada, and there is no available estimate of the incidence and mortality of epilepsy in all age groups in the Canadian population. This study aimed to measure the incidence, prevalence, mortality and the temporal trends for epilepsy in Saskatchewan between 2005 and 2010. Methods: The study used a population-based, retrospective cohort design with information from the Saskatchewan’s Population Health Registry databases for the periods of January 01, 2005 to December 31, 2010. The study cohort included the covered entire population of Saskatchewan with the identification of patients with epilepsy based on ICD codes. The incidence rate, prevalence, and standardized mortality ratio of epilepsy were measured over a period of six years and annually between 2005 and 2010 and age-standardized with the 2006 Canadian population. Results: The crude cumulative incidence of epilepsy was 63 per 100,000 person-years (age-standardized rate 62 per 100,000 person-years). Age-specific incidence was highest in the 75-79 age group (133.5 person 100,000 person-years). There was a significant decrease in the incidence of epilepsy over the study period. The incidence in self-declared Registered Indians (RI) was 95 per 100,000 person-years (age-standardized rate 122 per 100,000 person-years). It was significantly higher than the general population in most of the age groups. The overall prevalence was 8.5 in 1,000 people (9 per 1,000 if age-standardized to the 2006 Canadian population) with a male prevalence of 9 and a female prevalence of 8.4 per 1,000 person-years. There was a significant increase in the prevalence over time. The age-specific prevalence was high in 15-19 age group, 35-39 age group, and 80-84 age group. The cumulative SMR for the total group was 2.45 (2.7 in males and 2.2 in females). Age-specific SMRs were highest in the 10-14 age group. There was no temporal change in the SMR over the study period. Discussion: The findings of this study are consistent with incidence, prevalence and mortality studies from developed countries. However, the decrease in the incidence of epilepsy over time has been only seen previously in Nordic countries and needs more research. Significance: This study was the first in Canada to measure the incidence and all-cause mortality of epilepsy in all age groups. It provides core indicators of public health and healthcare needs of patients with epilepsy in Saskatchewan and Canada.