Efficacy and Safety of VNS Therapy or Continued Medication Management for Treatment of Adults with Drug-Resistant Epilepsy: Systematic Review and Meta-Analysis
Abstract Vagus nerve stimulation (VNS) Therapy® is an adjunctive neurostimulation treatment for people withdrug-resistant epilepsy (DRE) who are unwilling to undergo resective surgery, have had unsuccessfulsurgery or are unsuitable for surgery. A systematic review and meta-analysis were conducted todetermine the treatment effects of VNS Therapy as an adjunct to anti-seizure medications (ASMs) forthe management of adults with DRE.A literature search was performed in August 2020 of the Medline®, Medline® Epub Ahead of Print,Embase, and the Cochrane library databases. Outcomes examined included reduction in seizurefrequency, seizure freedom, ASM load, discontinuations, and serious adverse events (SAEs).Comparators included best medical practice, ASMs, low-stimulation or sham VNS Therapy.Four RCTs and six comparative observational studies were identified for inclusion. Against comparators,individuals treated with VNS had a significantly better odds of experiencing a ≥50% reduction in seizurefrequency (OR: 2.27 [95% CI: 1.47, 3.51]; p=0.0002), a ≥75% reduction in seizure frequency (OR: 3.56[95% CI: 1.59, 7.98]; p=0.002) and a reduced risk for increased ASM load (risk ratio: 0.36 [95% CI: 0.21,0.62]; p=0.0002). There was no difference in the odds of discontinuation or the rate of SAEs betweenVNS versus comparators.This meta-analysis demonstrated the benefits of VNS Therapy in people with DRE, which includedimprovement in seizure frequency without an increase in the rate of SAEs or discontinuations, therebysupporting the consideration of VNS Therapy for people who are not responding to ASMs and thoseunsuitable or unwilling to undergo surgery.