Prevalence and risk factors associated with drug-resistant epilepsy in adult epileptic patients

Abstract

Abstract Background Despite the plethora of pharmacotherapy and acquisition of new AEDs, there is a hard core of patients who persistently fail to respond to optimal treatment and continue to suffer from refractory seizures. We aimed to study the prevalence and risk factors for development of drug-resistant epilepsy (DRE). All adult patients with epilepsy (PWE) who attended the epilepsy outpatient clinic and were maintained on at least two anti-epileptic drugs (AEDs) were profiled for drug response in accordance with the International League against Epilepsy (ILAE) 2010 consensus definition for DRE. Data collected included demographics, detailed history of seizures, medications history, past medical and psychiatric history, electroencephalogram, and brain imaging findings. Results The prevalence rate of DRE was 21.3% in the study population. Significant variables on univariate analysis were the following: male gender (OR: 5.409, CI 1.661–17.617, p < 0.005), presence of GTC (OR: 4.187, CI 1.304–13.445, p < 0.016), no change in frequency after AEDs use (OR: 4.465, CI 1.211–16.468, p < 0.025), bad response to first AEDs (OR: 9.000, CI 2.437–33.244, p < 0.001), presence of developmental delay (OR: 10.612, CI 1.347–83.589, p < 0.025), presence of abnormal neurological examination (OR: 4.227, CI 1.145–15.601, p < 0.030), generalized epilepsy (OR: 3.886, CI 1.141–13.233, p < 0.030), presence of structural etiology (OR: 3.467, CI 1.152–10.431, p < 0.027), abnormal EEG findings (OR: 3.467, CI 1.152–10.431, p < 0.027), presence of focal activity in EEG (OR: 5.344, CI 1.155–24.713, p < 0.032), and abnormal imaging findings (OR: 3.524, CI 1.083–11.473, p < 0.036). In the logistic regression analysis, two variables were statistically significant: bad response to the first AED and no change in seizure frequencies with treatment. Our study showed that older age at seizure onset was a protective factor for DRE. Conclusions The current study suggests that significant risk factors for DRE are younger age at epilepsy onset, poor response to first AED and lack of change in seizure frequencies after adjusting treatment.