Estimating the potential savings with vagus nerve stimulation for treatment-resistant depression: a payer perspective

Efficacy of Deep Brain Stimulation for Treatment-Resistant Depression: Systematic Review and Meta-Analysis

BACKGROUND

Treatment-resistant depression affects about 30% of individuals with major depressive disorder. Deep brain stimulation is an investigational intervention for treatment-resistant depression with varied results. We undertook this meta-analysis to synthesize outcome data across trial designs, anatomical targets, and institutions to better establish efficacy and side-effect profiles.

METHODS

We conducted a systematic PubMed review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Seven randomized controlled trials (n = 198) and 8 open-label trials (n = 77) were included spanning 2009 to 2020. Outcome measures included Hamilton Depression Rating Scale or Montgomery-Åsberg Depression Rating Scale scores, as well as response and remission rates over time. Outcomes were tracked at the last follow-up and quantified as a time course using model-based network meta-analysis. Linear mixed models were fit to individual patient data to identify covariates.

RESULTS

Deep brain stimulation achieved 47% improvement in long-term depression scale scores, with an estimated time to reach 50% improvement of around 23 months. There were no significant subgroup effects of stimulation target, time of last follow-up, sex, age of disease onset, or duration of disease, but open-label trials showed significantly greater treatment effects than randomized controlled trials. Long-term (12-60 month) response and remission rates were 48% and 35%, respectively. The time course of improvement with active stimulation could not be adequately distinguished from that with sham stimulation, when available.

CONCLUSIONS

Deep brain stimulation produces significant chronic improvement in symptoms of treatment-resistant depression. However, the limited sham-controlled data do not demonstrate significant improvement over placebo. Future advancements in stimulation optimization and careful blinding and placebo schemes are important next steps for this therapy.

Cost-effectiveness and threshold analysis of deep brain stimulation vs. treatment-as-usual for treatment-resistant depression

Treatment-resistant depression (TRD) affects approximately 2.8 million people in the U.S. with estimated annual healthcare costs of $43.8 billion. Deep brain stimulation (DBS) is currently an investigational intervention for TRD. We used a decision-analytic model to compare cost-effectiveness of DBS to treatment-as-usual (TAU) for TRD. Because this therapy is not FDA approved or in common use, our goal was to establish an effectiveness threshold that trials would need to demonstrate for this therapy to be cost-effective. Remission and complication rates were determined from review of relevant studies. We used published utility scores to reflect quality of life after treatment. Medicare reimbursement rates and health economics data were used to approximate costs. We performed Monte Carlo (MC) simulations and probabilistic sensitivity analyses to estimate incremental cost-effectiveness ratios (ICER; USD/quality-adjusted life year [QALY]) at a 5-year time horizon. Cost-effectiveness was defined using willingness-to-pay (WTP) thresholds of $100,000/QALY and $50,000/QALY for moderate and definitive cost-effectiveness, respectively. We included 274 patients across 16 studies from 2009-2021 who underwent DBS for TRD and had ≥12 months follow-up in our model inputs. From a healthcare sector perspective, DBS using non-rechargeable devices (DBS-pc) would require 55% and 85% remission, while DBS using rechargeable devices (DBS-rc) would require 11% and 19% remission for moderate and definitive cost-effectiveness, respectively. From a societal perspective, DBS-pc would require 35% and 46% remission, while DBS-rc would require 8% and 10% remission for moderate and definitive cost-effectiveness, respectively. DBS-pc will unlikely be cost-effective at any time horizon without transformative improvements in battery longevity. If remission rates ≥8-19% are achieved, DBS-rc will likely be more cost-effective than TAU for TRD, with further increasing cost-effectiveness beyond 5 years.

Health Care Utilization Following Vagus Nerve Stimulation Therapy in Pediatric Epilepsy Patients From a Pediatric Accountable Care Organization

BACKGROUND

Vagus nerve stimulation has been a therapy for epilepsy approved by the US Food and Drug Administration (FDA) for patients 4 and older and shown efficacy and safety in younger pediatric patients.

METHODS

The authors performed a retrospective analysis utilizing Medicaid claims from an accountable care organization to measure the intervention of vagus nerve stimulation therapy in regard to unplanned health care utilization. Thirteen unique patients were included who had vagus nerve stimulation therapy who had at least 6 months of continuous enrollment in a managed Medicaid health plan. Comparison with 12 months of data before and after vagus nerve stimulation implantation was performed.

RESULTS

Patients had statistically significant fewer unplanned inpatient visits per patient per enrollment month after vagus nerve stimulation implantation.

CONCLUSION

Utilizing claims data, vagus nerve stimulation implantation demonstrates a reduction in unplanned hospitalizations.

The economic burden of treatment-resistant depression

BACKGROUND

Major depressive disorder (MDD) is a leading cause of disability, morbidity, and mortality worldwide. The lifetime prevalence in the United States is estimated at 17%. Treatment-resistant depression (TRD) is generally defined as failure to achieve remissions despite adequate treatment. About 30% of patients do not achieve remission after 4 different antidepressant treatment trials. A few studies have examined the economic burden of TRD, but none has investigated the cost associated with more chronic and extensive forms of TRD characterized by nonresponse to ≥4 treatment trials.

OBJECTIVE

The objective of this study was to compare the health care utilization (HCU) and direct medical expenditures of TRD patients with those of chronic MDD patients.

METHODS

Patients with chronic MDD (defined as ≥2 years of continuous treatment) and patients with TRD (defined as undergoing at least 4 different qualifying antidepressant therapy trials) were identified in the PharMetrics Patient-centric Database. The association between TRD and medical expenditures was measured by using multivariate regression analysis.

RESULTS

The classification of TRD had a clinically meaningful and statistically significant association with increased medical expenditures. Holding all else equal, the classification of TRD was associated with a 29.3% higher costs (P < 0.001) in medical expenditures compared with patients not meeting the study definition of TRD.

CONCLUSIONS

These results demonstrate that TRD is associated with significantly higher per-patient medical costs due to higher HCU. The findings suggest that the development of treatment alternatives for TRD is warranted. Limitations related to the use of secondary administrative data are noted.

A patient-level meta-analysis of studies evaluating vagus nerve stimulation therapy for treatment-resistant depression

Objective

To compare response and remission rates in depressed patients with chronic treatment-resistant depression (TRD) treated with vagus nerve stimulation (VNS) Therapy^® plus treatment as usual (VNS + TAU) or TAU alone in a meta-analysis using Bayesian hierarchical models.

Data sources and study selection

Six outpatient, multicenter, clinical trials that have evaluated VNS + TAU or TAU in TRD, including two single-arm studies of VNS + TAU (n = 60 and n = 74), a randomized study of VNS + TAU versus TAU (n = 235), a randomized study of VNS + TAU comparing different VNS stimulation intensities (n = 331), a nonrandomized registry of VNS + TAU versus TAU (n = 636), and a single-arm study of TAU (n = 124) to provide longer-term, control data for comparison with VNS-treated patients.

Data extraction

A systematic review of individual patient-level data based on the intent-to-treat principle, including all patients who contributed more than one post-baseline visit. Response was based on the Montgomery–Åsberg Depression Rating Scale (MADRS) and the Clinical Global Impressions scale’s Improvement subscale (CGI-I), as these were the two clinician-rated measures common across all or most studies. Remission was based on the MADRS.

Results

Outcomes were compared from baseline up to 96 weeks of treatment with VNS + TAU (n = 1035) versus TAU (n = 425). The MADRS response rate for VNS + TAU at 12, 24, 48, and 96 weeks were 12%, 18%, 28%, and 32% versus 4%, 7%, 12%, and 14% for TAU. The MADRS remission rate for VNS + TAU at 12, 24, 48, and 96 weeks were 3%, 5%, 10%, and 14% versus 1%, 1%, 2%, and 4%, for TAU. Adjunctive VNS Therapy was associated with a greater likelihood of response (odds ratio [OR] = 3.19, 95% confidence interval [CI]: 2.12, 4.66) and remission (OR = 4.99, CI: 2.93, 7.76), compared with TAU. For patients who had responded to VNS + TAU at 24 weeks, sustained response was more likely at 48 weeks (OR = 1.98, CI: 1.34, 3.01) and at 96 weeks (OR = 3.42, CI: 1.78, 7.31). Similar results were observed for CGI-I response.

Conclusion

For patients with chronic TRD, VNS + TAU has greater response and remission rates that are more likely to persist than TAU.

Medicare patient experience with vagus nerve stimulation for treatment-resistant depression

BACKGROUND

Major depressive disease (MDD) represents a cost burden to the US healthcare system: approximately one-third of MDD patients fail conventional treatment: multiple failures define treatment-resistant depression (TRD). Vagus nerve stimulation (VNS) therapy is an approved adjunctive treatment for TRD.

OBJECTIVE

To study the healthcare utilization experience of Medicare beneficiaries implanted with VNS (VNSBs) during Medicare coverage, compared with beneficiaries with TRD (TRDBs) and managed depression (Mdeps).

METHODS

A retrospective analysis of 100% standard analytic file (SAF) Medicare claims from 2006-2009 using specific criteria to identify a VNSB dataset, compared to TRDs and Mdeps datasets (extract of 5% sample SAF from 2001-2009) and 2009 general Medicare beneficiaries (GMBs). Comparative analysis included demographics, mortality, healthcare utilization, and costs.

RESULTS

Among patients meeting study criteria for VNSBs (n = 690), TRDBs (n = 4639), Mdeps (n = 7524), and GMBs (n > 36 million), VNSBs were on average: younger, more likely to be female, and white, with Medicare eligibility due to disability. Of the VNSBs in the 2-year post-implantation period: 5% died; 22% experienced no negative events (defined as hospitalizations for psychoses or poisoning, emergency room use, electroconvulsive therapy, or poisoning, suicidal ideation, or self-harm diagnoses); 29% experienced multiple negative events; and 41% had either a single hospitalization or only all-cause ER visits. VNSBs experiencing negative events had more complex co-occurring psychiatric diagnoses. The annual mortality rate for VNSBs post-implant was 19.9 deaths per 1000 patient years, compared with 46.2 (CI: 41.9-51.6) and 46.8 (CI: 43.4-50.4) deaths for TRDBs and Mdeps, respectively. The medical costs per patient-year post-VNS implantation for VNSBs ($8749) was similar to the Mdeps ($8960; CI $8555-$9381) and was substantially lower than TRDBs ($13,618; CI $12,937-$14,342).

CONCLUSIONS

VNSBs achieving positive health outcomes (measured by lack of negative events post-implantation) tend to have fewer psychiatric co-occurring conditions. Lowered costs post-implantation with evidence of response to VNS suggest the therapy represents an option for carefully screened TRDBs who have failed other therapies.

LIMITATIONS

Administrative data are missing pharmaceuticals and clinical measures. Data for the VNS population were not available pre-implantation for comparison to post-implantation experience. Cost comparisons are adjusted for missing costs in the VNS dataset.

Pretreatment cerebral metabolic activity correlates with antidepressant efficacy of vagus nerve stimulation in treatment-resistant major depression: a potential marker for response?

BACKGROUND

Pretreatment brain activity in major depressive disorder correlates with response to antidepressant therapies, including pharmacotherapies and transcranial magnetic stimulation. The purpose of this trial was to examine whether pretreatment regional metabolic activity in selected regions of interest (ROIs) predicts antidepressant response following 12 months of vagus nerve stimulation (VNS) in 15 patients with treatment-resistant major depression (TRMD).

METHODS

Fluorodeoxyglucose positron emission tomography (FDG PET) was used to assess regional mean relative cerebral metabolic rate for glucose (CMRGlu) in four ROIs (anterior insular, orbitofrontal, anterior cingulate, and dorsolateral prefrontal cortices) at baseline (prior to VNS activation). Depression severity was assessed at baseline and after 12 months of VNS using the Hamilton Depression Rating Scale (HDRS), with response defined as ≥ 50% reduction in HDRS from baseline.

RESULTS

Baseline CMRGlu in the anterior insular cortex differentiated VNS responders (n=11) from nonresponders (n=4) and correlated with HDRS change (r=.64, p=.01). In a regression analysis, lower anterior insular cortex CMRGlu (p=.004) and higher orbitofrontal cortex CMRGlu (p=.047) together predicted HDRS change (R(2)=.58, p=.005). In a whole brain, voxel-wise analysis, baseline CMRGlu in the right anterior insular cortex correlated with HDRS change (r=.78, p=.001).

LIMITATIONS

Sample size was small, limiting statistical power; patients remained on their psychiatric medications; study was open-label and uncontrolled.

CONCLUSIONS

This preliminary study suggests that pretreatment regional CMRGlu may be useful in predicting response to VNS in TRMD patients.

Systematic review and meta-analysis of vagus nerve stimulation in the treatment of depression: variable results based on study designs

PURPOSE

To determine the efficacy of vagus nerve stimulation (VNS) for treatment of depression.

METHODS

We conducted a systematic review and meta-analysis of analytical studies. Efficacy was evaluated according to severity of illness and percentage of responders.

RESULTS

We identified 687 references. Of these, 14 met the selection criteria and were included in the review. The meta-analysis of efficacy for uncontrolled studies showed a significant reduction in scores at the Hamilton Depression Rating Scale endpoint, and the percentage of responders was 31.8% ([23.2% to 41.8%], P<0.001). However, the randomised control trial which covered a sample of 235 patients with depression, reported no statistically significant differences between the active intervention and placebo groups (OR=1.61 [95%CI 0.72 to 3.62]; P=0.25). To study the cause of this heterogeneity, a meta-regression was performed. The adjusted coefficient of determination (R2(Adj)) was 0.84, which implies that an 84% variation in effect size across the studies was explained by baseline severity of depression (P<0.0001).

CONCLUSION

Currently, insufficient data are available to describe VNS as effective in the treatment of depression. In addition, it cannot be ruled out that the positive results observed in the uncontrolled studies might have been mainly due to a placebo effect.