Analysis of pharmacotherapy regimen and costs in patients with drug-resistant epilepsy following vagus nerve stimulation therapy: a single-center study (Poland)

Synergistic effects of vagus nerve stimulation and antiseizure medication

INTRODUCTION

Vagus nerve stimulation (VNS) is an effective, non-pharmacological therapy for epileptic seizures. Until now, favorable combinations of different groups of antiseizure medication (ASM) and VNS have not been sufficiently addressed. The aim of this study was to identify the synergistic effects between VNS and different ASMs.

METHODS

We performed an observational study of patients with epilepsy who were implanted with VNS and had a stable ASM therapy during the first 2 years after the VNS implantation. Data were collected from the Mainz Epilepsy Registry. The efficacy of VNS depending on the concomitantly used ASM group/individual ASMs was assessed by quantifying the responder rate (≥ 50% seizure reduction compared to the time of VNS implantation) and seizure freedom (absence of seizures during the last 6 months of the observation period).

RESULTS

One hundred fifty one patients (mean age 45.2 ± 17.0 years, 78 females) were included in the study. Regardless of the used ASM, the responder rate in the whole cohort was 50.3% and the seizure freedom was 13.9%. Multiple regression analysis showed that combination of VNS with synaptic vesicle glycoprotein (SV2A) modulators (responder rate 64.0%, seizure freedom 19.8%) or slow sodium channel inhibitors (responder rate 61.8%, seizure freedom 19.7%) was associated with a statistically significant better responder rate and seizure freedom than combinations of VNS and ASM with other mechanism of action. Within these ASM groups, brivaracetam showed a more favorable effect than levetiracetam, whereas lacosamide and eslicarbazepine were comparable in their effects.

CONCLUSION

Our data suggest that the combination of VNS with ASMs belonging to either SV2A modulators or slow sodium channel inhibitors could be optimal to achieve a better seizure control following VNS. However, these preliminary data require further validation under controlled conditions.

Health Technology Assessment Report on Vagus Nerve Stimulation in Drug-Resistant Epilepsy

Background: Vagus nerve stimulation (VNS) is a palliative treatment for medical intractable epileptic syndromes not eligible for resective surgery. Health technology assessment (HTA) represents a modern approach to the analysis of technologies used for healthcare. The purpose of this study is to assess the clinical, organizational, financial, and economic impact of VNS therapy in drug-resistant epilepsies and to establish the congruity between costs incurred and health service reimbursement. Methods: The present study used an HTA approach. It is based on an extensive detailed bibliographic search on databases (Medline, Pubmed, Embase and Cochrane, sites of scientific societies and institutional sites). The HTA study includes the following issues: (a) social impact and costs of the disease; (b) VNS eligibility and clinical results; (c) quality of life (QoL) after VNS therapy; (d) economic impact and productivity regained after VNS; and (e) costs of VNS. Results: Literature data indicate VNS as an effective treatment with a potential positive impact on social aspects and on quality of life. The diagnosis-related group (DRG) financing, both on national and regional levels, does not cover the cost of the medical device. There was an evident insufficient coverage of the DRG compared to the full cost of implanting the device. Conclusions: VNS is a palliative treatment for reducing seizure frequency and intensity. Despite its economic cost, VNS should improve patients’ quality of life and reduce care needs.