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

Abstract

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.