Clinical and economic impact of vagus nerve stimulation therapy in patients with drug-resistant epilepsy

Abstract

We evaluated long-term medical and economic benefits of vagus nerve stimulation (VNS) therapy in drug-resistant epilepsy. A pre-post analysis was conducted using multistate Medicaid data (January 1997-June 2009). One thousand six hundred fifty-five patients with one or more neurologist visits with epilepsy diagnoses (ICD-9 345.xx, 780.3, or 780.39), one or more procedures for vagus nerve stimulator implantation, one or more antiepileptic drugs (AEDs), and 6 or more months of continuous Medicaid enrollment pre- and post-VNS were selected. The pre-VNS period was 6 months. The post-VNS period extended from implantation to device removal, death, Medicaid disenrollment, or study end (up to 3 years). Incidence rate ratios (IRRs) and cost differences ($2009) were estimated. Mean age was 29.4 years. Hospitalizations decreased post-VNS compared with pre-VNS (adjusted IRR=0.59, P<0.001). Grand mal status events decreased post-VNS compared with pre-VNS (adjusted IRR=0.79, P<0.001). Average total health care costs were lower post-VNS than pre-VNS ($18,550 vs $19,945 quarterly, P<0.001). VNS is associated with decreased resource utilization and epilepsy-related clinical events and net cost savings after 1.5 years.