Response to “A randomized controlled trial of the ketogenic diet in refractory childhood epilepsy”
With regard to the baseline characteristic of the both the ketogenic diet (KD) group and the care as usual group (CAU), there appear to be marked differences in the etiology of epilepsy among the 2 groups. Specifically, in the KD group, a total of 34.4% of patients had a genetically mediated epilepsy, 7.7% had a structural cause, and 57.7% had an unknown etiology. In contrast, in the CAU group, 4.5%, 45.5%, and 50% of patients had genetic, structural, and unknown etiologies, respectively, raising the possibility that etiology itself could be a contributing factor in the trial outcomes. Additionally, the wide range of ages represented in the cohorts could also lead to issues with dietary compliance, seizure documentation, and other measures.
With respect to the design methodology, we have to wonder whether the absence of blinding in the evaluating physicians and study personnel could result in an unintentional source of bias, possibly in such factors as adjustments in antiepileptic dose adjustments, which occurred more frequently in the AED treatment group. Additionally, the design and analyzes do not appear to fully address the potential influence of confounding variables.