Long-term clinical outcomes and economic evaluation of the ketogenic diet versus care as usual in children and adolescents with intractable epilepsy

OBJECTIVE: To examine long-term retention rate, clinical outcomes, cost-utility and cost-effectiveness of the Ketogenic Diet (KD) compared with care as usual (CAU) in children and adolescents with intractable epilepsy from a societal perspective.

METHODS: Participants were randomized into a KD or CAU group. Seizure frequency, quality adjusted life years (QALYs), side-effects, seizure severity, health care costs, production losses, patient and family costs were assessed at baseline and during 16-months of follow-up. Incremental cost-effectiveness ratios (ICERs) (i.e. cost per QALY and cost per responder) and cost-effectiveness acceptability curves are presented.

RESULTS: 48 children were included in the analyses of this study (26 from KD group). In total, 58% of the KD group completed the follow-up of 16 months; 11 dropped-out for various reasons. At 16 months, 35% of the KD participants had a seizure reduction≥50% from baseline, compared with 18% of the CAU participants. Mean costs per patient in the CAU group were €53,367 (extrapolated) compared to €61,019 per patient in the KD group, resulting in an ICER of €46,564 per responder. Cost per QALY rose well above any acceptable ceiling ratio. At 4-months' follow-up, the KD group showed significantly more gastro-intestinal problems compared to the CAU group. At 16 months, the KD group reported fewer problems compared to CAU. Furthermore, 46.2% of the KD group reported a decrease in severity of their worst seizure compared to 32% of the CAU group.

CONCLUSION: The KD group resulted in more responders and showed greater improvement on seizure severity. Furthermore, the KD did not lead to worsening of side-effects other than gastro-intestinal problems (only at 4 months' follow-up). However, as only a minimal difference in QALYs was found between the KD group and the CAU group, the resulting cost per QALY ratios were inconclusive.