Abstracts

Rationale: Epilepsy is a condition that affects 0.6% of Canadian population. About 35-40% of patients with epilepsy may develop drug resistant epilepsy (DRE). Patients with drug resistant epilepsy have an increased risk of mortality and decreased quality of life. Therefore, identifying risk factors associated with drug resistant epilepsy will allow us to provide aggressive medical treatment early in the course of the disease and improve quality of life of patients. This is a case-control study designed to identify risk factors associated with drug resistant focal epilepsy in adults.Methods: Subjects were selected from the Saskatchewan epilepsy program according to the inclusion criteria. Chart review of subjects were completed according to the data abstract tool specifically designed for this project. The inclusion criteria included age > 18 years, focal epilepsy determined by clinical correlation and EEG and drug resistant epilepsy determine by ILAE criteria. We calculated odds ratio with a 95% CI and P < 0.05.Results: 95 subjects were included in this study. Forty eight patients had DRE (cases) and forty seven did not have DRE (controls). The drug resistant group had a mean age of 38.9 with a standard deviation of 14.1 compared to the control group with a mean age of 48.5 and a standard deviation of 16.0 (p =0.03). The drug resistant group had a mean age at diagnosis of epilepsy of 18.5 with a standard deviation of 15.4 compared to the control group with a mean of 32.9 and standard deviation of 23.0. (p = 0.001). The main risk factors identified in this study were; cortical dysplasia OR 7.85, CI 0.93-66.6, p 0.069 and mesiotemporal sclerosis OR 2.31, CI 0.91-5.91, p 0.12. In addition, previous history of brain surgery was a protective factor OR 0.18, CI 0.04-0.09, p = 0.05.Conclusions: Although, it is too early in this study to draw precise conclusion, there are significant correlations seen which may be helpful. Younger age of diagnosis of focal epilepsy definitely has a correlation with developing drug resistant epilepsy. Therefore, precautions may be taken to treat younger patients more aggressively and provide appropriate early surgical interventions. Cortical dysplasia and Mesiotemporal sclerosis may have a tendency towards developing drug resistant epilepsy. However, a larger sample size is required to provide a definite correlation. History of brain surgery is definitely protective against drug resistant focal epilepsy and may be easier to control with antiepileptic drugs.