Repetitive Transcranial Magnetic Stimulation for Treatment-Resistant Depression: An Economic Analysis.

Background: Major depressive disorder (MDD, 10% over a person's lifetime) is common and costly to the health system. Unfortunately, many MDD cases are resistant to treatment with antidepressant drugs and require other treatment to reduce or eliminate depression. Electroconvulsive therapy (ECT) has long been used to treat persons with treatment-resistant depression (TRD). Despite its effectiveness, ECT has side effects that make patients intolerant to the treatment, or they refuse to use it. Repetitive transcranial magnetic stimulation (rTMS), which has fewer side effects than ECT and might be an alternative for TRD patients who are ineligible for or unwilling to undergo ECT, has been developed to treat TRD.

Objectives: This analysis evaluates the cost-effectiveness of rTMS for patients with TRD compared with ECT or sham rTMS and estimates the potential budgetary impact of various levels of implementation of rTMS in Ontario.

Review methods: A cost-utility analysis compared the costs and health outcomes of two treatments for persons with TRD in Ontario: rTMS alone compared with ECT alone and rTMS alone compared with sham rTMS. We calculated the six-month incremental costs and quality-adjusted life-years (QALYs) for these treatments. One-way and probabilistic sensitivity analyses were performed to test the robustness of the model's results. A 1-year budget impact analysis estimated the costs of providing funding for rTMS. The base-case analysis examined the additional costs for funding six centres, where rTMS infrastructure is in place. Sensitivity and scenario analyses explored the impact of increasing diffusion of rTMS to centres with existing ECT infrastructure. All analyses were conducted from the Ontario health care payer perspective.

Results: ECT was cost effective compared to rTMS when the willingness to pay is greater than $37,640.66 per QALY. In the base-case analysis, which had a six-month time horizon, the cost and effectiveness for rTMS was $5,272 and 0.31 quality-adjusted life-years (QALYs). The cost and effectiveness for ECT were $5,960 and 0.32 QALYs. This translates in an incremental cost-effectiveness ratio of $37,640.66 per QALY gained for ECT compared to rTMS. When rTMS is compared with sham rTMS, an additional $2,154.33 would be spent to gain 0.02 QALY. This translates to an ICER of $98,242.37 per QALY gained. Probabilistic sensitivity analysis showed that the probability of rTMS being cost-effective compared to sham rTMS was 2% and 45% at the thresholds of $50,000 and $100,000 per QALY gained, respectively.

Conclusions: Repetitive transcranial magnetic stimulation may be cost-effective compared to sham treatment in patients with treatment-resistant depression, depending on the willingness-to-pay threshold.