Deep brain stimulation for Alzheimer disease: a decision and cost-effectiveness analysis.

Alzheimer disease (AD) is characterized by impairments in memory function. Standard AD treatment provides marginal improvements in this domain. Recent reports, however, suggested that deep brain stimulation (DBS) may result in improved memory. Given significant equipment costs and health expenses required for DBS surgery, we determine clinical and economic thresholds required for it to be as effective as standard AD treatment. Literature review yielded annual AD progression probabilities, health-related quality of life (QoL), and costs by AD stage. Our 5-year decision analysis model compared cumulative QoL in quality-adjusted life years (QALYs) and costs of standard therapy to theoretical DBS treatment of various success rates, using known complication rates and QoL data. The base case was a patient with mild-stage AD. DBS success was defined as regression to and maintenance of minimal stage AD, which was defined as midway between mild and no dementia, for the first year, and continuation of the natural course of AD for the remaining 4 years. Compared to standard treatment alone, DBS for mild-stage AD requires a success rate of 3% to overcome effects of possible surgical complications on QoL. If DBS can be delivered with success rates above 20% ($200 K/QALY) or 74% ($50 K/QALY) for mild AD, it can be considered cost-effective. Above a success rate of 80%, DBS treatment is both clinically more effective and more cost-effective than standard treatment. Our findings demonstrate that clinical and economic thresholds required for DBS to be cost-effective for AD are relatively low.