Abstracts

Rationale: Seventy% of patients with epilepsy have their seizures easily controlled, but thirty% develop intractable epilepsy, seizures resistant to two or three antiepileptic medications (AEDs). Obtaining seizure control with more antiepileptic medications in this group is disappointingly small, only about 3-5%. Short-term outcome studies show greater success on the ketogenic diet (KD). However, long-term efficacy of the KD is not well defined. The aim of this study is to determine the success of maintaining seizure freedom long-term in children with intractable epilepsy on the KD. Methods: The Institutional Review Board approved this retrospective chart review. Between 1/1/1994 and 6/31/2009, 410 patients started the KD at The Children s Hospital of Philadelphia. 276 charts were reviewed. Demographic information was collected. Seizure freedom was defined as having at least one month of seizure freedom at any point during KD treatment. The clinical course and risk factors for seizure relapse were assessed. Statistical analysis included Kaplan Meier survival curves. Results: Sixty-five patients of the 276 met our criteria for seizure freedom on the KD. Males comprised 57%. The median age of starting the KD was four years old (range 0.3-16 years old). Seventy seven% had failed ?4 AEDs prior to starting the diet. The majority of patients (69%) were having daily seizures. Abnormal brain MRIs were present in 52% with periventricular leukomalacia (23%) and dysplasias (20%) as the most common abnormalities. The time from KD initiation to seizure freedom ranged from 1-20 months (median 1.5 months). The median time to seizure recurrence was less than three months. The chance of remaining completely seizure free by 18 months was only 3%. Despite this small chance of sustained seizure freedom the seizure frequency in those who recurred was less than their baseline seizure frequency. Seventy-two% were categorized as early responders, patients who became seizure free within the first 3 months of KD initiation, and 28% were late responders, those who became seizure free after 3 months. Being a late responder was not a risk factor for seizure recurrence (hazard ratio = 1.08). Abnormal brain MRIs, age of seizure onset, ? 4 AED failures prior to the KD and weaning AEDs within 3 months of KD initiation were not statistically significant risk factors for seizure relapse. Twelve of the 65 children remained seizure free throughout KD treatment, which ranged from 0.6-6 years. At their last follow up appointment 53% of the patients were on fewer AED s than prior to the KD. Conclusions: Based on this long-term analysis, the KD is a beneficial antiepileptic treatment for children with intractable epilepsy. The probability of remaining completely seizure free over the long term is low. However, the seizure frequency of those that recurred was far less than before the diet. The diet also allowed for a decrease in the total number of AEDs, which often have many side effects. No baseline clinical features were identified as risk factors for seizure recurrence on the KD.