Comparison of healthcare resource utilization in pediatric patients with refractory epilepsy: Vagus nerve stimulation and medical treatment cohorts

Impact of Vagus Nerve Stimulation for the Treatment of Drug-Resistant Epilepsy on Patterns of Use and Cost of Health Care Services and Pharmacotherapy: Comparisons of the 24-Month Periods Before and After Implantation

PURPOSE

This study examines the impact of vagus nerve stimulation (VNS) as treatment for drug-resistant epilepsy (DRE) on the use and cost of health care services and pharmacotherapy.

METHODS

Using a large US health care claims database, we identified all patients with DRE who underwent VNS between January 1, 2012 and December 31, 2019. VNS implantation date was designated as the index date, and patients had to be continuously enrolled for the 24-month period before this date (preindex period). Outcomes included all-cause and epilepsy-related hospitalization, emergency department (ED) visits, and health care costs; health care claims resulting in an epilepsy diagnosis and all claims for antiseizure medications were deemed epilepsy related. Preindex data, except care related to preoperative medical clearance for VNS, were used to estimate multivariate regression models predicting outcomes during the 24-month postindex period (follow-up period). Predicted outcomes during follow-up were then compared with observed values. As a sensitivity analysis, we also replicated all analyses among subgroups defined by comorbid depression.

FINDINGS

A total of 659 patients underwent VNS for DRE and met the selection criteria. For the composite outcome of all-cause hospitalizations and ED visits, observed values were 42% lower than expected during the 24-month follow-up period; for the composite outcome of epilepsy-related hospitalizations and ED visits, observed values were 49% lower (P < 0.001 for both). Observed mean total all-cause costs, inclusive of costs of the procedure, were not significantly different than expected costs by month 19 of follow-up; mean total epilepsy-related costs were comparable by month 18. Findings were similar in subgroups with and without depression, although nominally greater differences (observed - expected) were seen in those with comorbid depression.

IMPLICATIONS

Our findings suggest that VNS is associated with decreased risk of hospitalization or ED visits (all cause and epilepsy related) during the 2-year period subsequent to implantation and may become cost-neutral within 2 years of implantation (vs continued medical management of DRE without VNS). Although expected outcomes were estimated based on the 24-month period before implantation, the degree to which they approximated what would have happened in the absence of VNS is unknowable. Further research is needed to better understand the extend and duration of the impact of VNS on seizure frequency and severity and health-related quality of life, including its performance among those with and without comorbid depression.

Pediatric Vagus Nerve Stimulation: Case Series Outcomes and Future Directions

BACKGROUND

Vagus nerve stimulation (VNS) is a neuromodulatory procedure most extensively studied as an adjunct to medically refractory epilepsy. Despite widespread adoption and decades of clinical experience, clinical predictors of response to VNS remain unclear.

OBJECTIVE

To evaluate a retrospective cohort of pediatric patients undergoing VNS at our institution to better understand who may benefit from VNS and identify factors which may predict response to VNS.

METHODS

We conducted a retrospective cohort study examining pediatric patients undergoing VNS over nearly a 20-year span at a single institution. Presurgical evaluation, including demographics, clinical history, and diagnostic electroencephalogram, and imaging findings were examined. Primary outcomes included VNS response.

RESULTS

Two hundred ninety-seven subjects were studied. The mean age at surgery was 10.1 (SD = 4.9, range = 0.8-25.3) years; length of follow-up was a mean of 4.6 years (SD = 3.5, median = 3.9 years, range 1 day-16.1 years). There was no association between demographic factors, epilepsy etiology, or genetic basis and VNS outcomes. There was an association between reduction in main seizure type with positive MRI finding. Of all MRI findings analyzed, brain atrophy was significantly associated with worse VNS outcomes, whereas dysplastic hippocampus and chronic periventricular leukomalacia findings were found to be associated with improved outcomes. Increased seizure semiology variability and seizure type were also associated with improved seizure outcomes.

CONCLUSION

Predicting response to VNS remains difficult, leading to incompletely realized benefits and suboptimal resource utilization. Specific MRI findings and increased seizure semiology variability and type can help guide clinical decision making and patient counseling.

Comparison of utilization and cost of healthcare services and pharmacotherapy following implantation of vagus nerve stimulation vs. responsive neurostimulation or deep brain stimulation for the treatment of drug-resistant epilepsy: analyses of a large United States healthcare claims database

AIM

Vagus nerve stimulation (VNS), responsive neurostimulation (RNS), and deep brain stimulation (DBS) all are options for drug-resistant epilepsy (DRE). However, little is known about how the choice of neurostimulation impacts subsequent healthcare costs.

MATERIALS AND METHODS

We used a large US healthcare claims database to identify all patients with epilepsy who underwent neurostimulation between 2012 and 2019. Eligible patients were identified and stratified based on procedure received (VNS vs. RNS/DBS). VNS patients were matched by propensity scoring to RNS/DBS patients. Use and cost of healthcare resources and pharmacotherapy were ascertained over the 24-month period following neurostimulation, incorporating all-cause and epilepsy-related measures. Disease-related care was defined based on diagnoses of claims for medical care and relevant pharmacotherapies.

RESULTS

Seven hundred and ninety-two patients met all selection criteria. VNS patients were younger, were prescribed a higher pre-index mean number of anti-seizure medications (ASMs), and had higher pre-index levels of use and cost of epilepsy-related healthcare services. We propensity matched 148 VNS patients to an equal number of RNS/DBS patients. One year following index date (inclusive), mean total all-cause healthcare costs were 50% lower among VNS patients than RNS/DBS patients, and mean epilepsy-related costs were 55% lower; corresponding decreases at the two-year mark were 41% and 48%, respectively.

LIMITATIONS

Some clinical variables, such as seizure frequency and severity, quality of life, and functional status were unavailable in the database, precluding our ability to comprehensively assess differences between devices. Administrative claims data are subject to billing code errors, inaccuracies, and missing data, resulting in possible misclassification and/or unmeasured confounding.

CONCLUSIONS

After matching, VNS was associated with significantly lower all-cause and epilepsy-related costs for the two-year period following implantation. All-cause and epilepsy-related costs remained statistically significantly lower for VNS even after costs of implantation were excluded.