Uncontrolled epilepsy is not necessarily the same as drug-resistant epilepsy: Differences between populations with newly diagnosed epilepsy and chronic epilepsy

Background: A proportion of patients with seemingly "uncontrolled" epilepsy could still control their epilepsy with further pharmacological manipulations. It is possible that their epilepsy might not be truly "drug-resistant". We audited the patients with "uncontrolled epilepsy" using the recent ILAE definition of drug-resistant epilepsy. Methods: Patients with newly diagnosed epilepsy at Glasgow and patients with chronic epilepsy treated in Hong Kong were independently assessed at their last clinic visit. If the patient was not seizure-free, the epilepsy was considered "uncontrolled". In this latter situation, if the patient had adequate trials of two or more tolerated, appropriately chosen, and appropriately used AED schedules, the epilepsy was classified as "drug-resistant" in accordance with the ILAE definition. If not, the outcome was classified as "undefined", and the reason(s) for this was documented. Results: In the newly diagnosed cohort with uncontrolled epilepsy (n = 311), outcome was "undefined" in 175 (56%). The most common reasons were trying just one AED usually at the patient's behest (n = 68; 39%); intermittent compliance (60; 34%); adverse effects at low dosage (51; 29%); inadequate dosing (49; 28%); social issues such as imprisonment, alcohol, and recreational drug use (34; 19%); psychiatric problems affecting documentation, attendance, etc. (32; 18%); patient choice accepting less than optimal control (14; 8%); and seizure freedom of less than 12. months (12.7%). In the chronic cohort of 194 patients with uncontrolled epilepsy, drug responsiveness was "undefined" in just 79 (41%). The most common reasons were inadequate use of the AED(s) (35; 44%), followed by a lack of information on treatment response in the medical records (18; 23%) and failure of only one adequately used AED (11; 14%). Conclusion: Uncontrolled epilepsy is not necessarily the same as drug-resistant epilepsy. Efforts should be made to understand why a patient is not seizure-free so that appropriate adjustment in AED regimen can be taken to enable the patient to attain long-term seizure freedom.