Abstracts

Rationale: DRE is associated with poor health outcomes and high healthcare resource utilization. VNS is indicated for use in patients with DRE and has been shown to reduce seizure frequency and may improve quality of life. We previously demonstrated in both commercially insured and Medicare beneficiaries that VNS is also associated with significantly lower levels of: (1) admissions and emergency department (ED) visits; and (2) healthcare costs (all vs. what was expected had VNS not been implanted). While this work has increased knowledge of positive economic and health implications associated with VNS use, the degree to which it reflects the experience of Medicaid enrollees with DRE has not been explored.

Methods: We used healthcare claims data obtained from the US Center for Medicare and Medicaid Services (CMS) to identify Medicaid enrollees with DRE who underwent VNS implantation between 1 January 2011 and 31 December 2020. The earliest date on which implantation was noted was designated the index date. We excluded patients: (1) without an epilepsy diagnosis on index date; (2) without ASM claims in the year prior to implantation; and (3) with < 2 years continuous enrollment immediately prior to index. Use of healthcare resources and pharmacotherapy during the 2-year pre-index period, excluding that deemed related to preparing for implantation, was used to develop regression models that estimated expected values over the 24-month post-index period (“follow-up”). Observed outcomes during follow-up were contrasted to those expected and were assessed alternatively using an all-cause and epilepsy-related basis; the latter defined as all medical care claims with epilepsy diagnoses and all ASM dispenses.

Results: A total of 2,283 patients met all selection criteria. Expected rates for the composite of hospitalizations and emergency department (ED) visits were higher than observed for all-cause (37.84 vs. 25.84 events per 100 person-months (PMs), P < 0.001) and epilepsy-related (29.78 vs. 13.87 events per 100 PMs, P < 0.001) outcomes. In the 23 months after the month of implantation, observed all-cause monthly costs were $1,177 less than expected; observed epilepsy related monthly costs were $1,621 lower (Figure 1). Differences between cumulative observed vs. expected costs were comparable by month 18.