PMH19 Cost-Effectiveness of Vagus Nerve Stimulation for Treatment-Resistant Depression in the United Kingdom

Abstract

Treatment-resistant depression (TRD) is a debilitating condition with a significant impact on patients and carers, and health care spending. Treatment resistance occurs in approximately 30% of individuals affected by Major Depressive Disorder. This analysis explored the potential cost-effectiveness of introducing vagus nerve stimulation (VNS) adjunctive to treatment as usual (TAU) for patients with TRD who have failed on ≥4 adequate anti-depressant treatments in England and Wales. A Markov model simulated patient transitions between health states defined by type of treatment, battery status and disease severity, as defined by Montgomery–Åsberg Depression Rating Scale score. Effectiveness was based on individual patient data from the D-21 dosing trial and the D-23 observational study assessing the effectiveness of VNS plus TAU compared to TAU alone. Hypothetical patients included those with moderate and severe depression at baseline, reflecting the population that would be eligible for VNS. The model had a 10-year time horizon and took a UK NHS perspective. Longer time horizons were also explored, as was a societal perspective. Costs and benefits were discounted at a rate of 3.5%. One-way deterministic, probabilistic and scenario analyses were undertaken to test various model inputs. When considering direct costs, the total cost of the VNS strategy was £42,589 compared to £29,928 for TAU. VNS generated 0.42 incremental quality-adjusted life-years (QALYs) compared to TAU, giving an incremental cost-effectiveness ratio (ICER) of £29,995 per QALY gained. When societal costs were considered, the VNS strategy dominated. In the probabilistic sensitivity analysis, VNS had a 50% probability of being cost-effective at a willingness-to-pay threshold of £30,000 per QALY. Extending the time horizon of the analysis to 20 years resulted in an ICER of £25,764. This analysis shows that VNS in addition to TAU could represent a cost-effective option for patients with TRD in the UK.