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

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.

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).

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.

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).

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.

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.