Ketogenic diet treatment in adults with refractory epilepsy.

The ketogenic diet (KD) is an effective treatment for refractory epilepsy in children. It has been little studied in adults. We evaluated the efficacy of, safety of, and compliance with adjunctive KD treatment in adults with refractory epilepsy in a prospective open-label pilot study. Seizure frequency was evaluated for 4 baseline months, 4 months of adjunctive KD treatment with a 3:1 [fat]:[carbohydrate+protein] weight ratio and 1600 kcal/day, and subsequent elective open-ended KD treatment. A 3:1 ratio was used instead of the 4:1 ratio employed in children because of greater palatability. Average monthly seizure frequency and seizure-free months at baseline were compared with KD months 1-4 (phase 1) and all KD treatment (phase 2). Diet compliance was evaluated with daily urine ketone body and monthly serum β-hydroxybutyrate levels. Twelve subjects were treated for up to 26 months. Three stopped treatment early for psychosocial reasons (n=2) or lack of efficacy. Seven of the 12 subjects were fully compliant, 4 were partially compliant, and 1 was noncompliant. Mean seizure frequency declined by 38.4 and 44.1% for phases 1 and 2, respectively (P=0.04). Forty-two percent and 50% of subjects had a >50% reduction during phases 1 and 2, respectively. Four of 12 subjects (33%) had a >85% seizure reduction. Twenty percent of subject-months were seizure free at baseline versus 56% during both study phases (P=0.04). Adverse effects were mild: nausea, vomiting, diarrhea, constipation, and weight loss.