Predicting drug resistance in adult patients with generalized epilepsy: A case-control study

Using an adult cohort of patients with generalized epilepsy, we aimed to identify risk factors for development of drug-resistant epilepsy (DRE), which if identifiable would allow patients to receive earlier treatment and more specifically individualized treatment plans.

For the case-control study, 118 patients with generalized epilepsy (GE) between the ages of 18 and 75 were included after selection from a database of 800 patients referred from throughout the Saskatchewan Epilepsy Program. Definitions were used in accordance with ILAE criteria. The odds ratio and its confidence interval were calculated. We performed a logistic regression analysis.

Forty-four (37%) patients fulfilled the definition of DRE (cases), and seizures in 74 (63%) patients were not intractable (controls). Patients with DRE were significantly younger than the controls at the onset of epilepsy (6.6 vs. 18.8 years, p=<0.001). Significant variables on univariate analysis were the following: epilepsy diagnosed prior to 12 years (OR: 12.1, CI: 4.8-29.9, p<0.001), previous history of status epilepticus (OR: 15.1, CI: 3.2-70.9, p<0.001), developmental delay (OR: 12.6, CI: 4.9-32, p<0.001), and cryptogenic epilepsy (OR: 10.5, CI: 3.9-27.8, p<0.001). Our study showed some protective factors for DRE such as a good response to first AED, idiopathic etiology, and history of febrile seizures. In the logistic regression analysis, two variables remained statistically significant: developmental delay and more than one seizure type.

Our study has identified a set of variables that predict DRE in patients with generalized epilepsy. Risk factors identified in our study are similar to those previously identified in pediatric studies, however, our study is specifically tailored to adult patients with generalized epilepsy.