Objective: To conduct a cost-effectiveness analysis comparing the addition of memantine to standard care (that is, without acetylcholinesterase inhibitors) with standard care alone in moderate-to-severe Alzheimer disease (AD) in Canada.
Methods: A 2-year Markov model estimated clinical effects in terms of quality-adjusted life years (QALYs) and time in complete dependence as well as societal costs in four 6-month cycles. Health states were defined by AD severity assessed with the Mini-Mental State Examination (moderate = 10 to 19; severe < 10), by level of dependence in activities of daily living, and by death. Transition probabilities were estimated by combining data of patients with moderate-to-severe AD from all relevant clinical trials. QALYs were estimated from a UK epidemiologic study. The initial distribution and use of medical and support services for each health state was obtained from the Canadian Study on Health and Aging with current estimates of frequency of use and unit prices applied.
Results: Compared with standard care, the memantine strategy saved more than 1 month of complete dependence and produced 0.03 additional QALYs, with no additional cost. Probabilistic sensitivity analyses give an 83.3% chance that memantine treatment is cost-neutral, an 89.5% chance of its being cost-effective if the decision maker is willing to pay $20 000 for a QALY, and a 96.2% chance with a willingness to pay $100 000 per QALY. Robustness of results was confirmed through 1-way and scenario-based sensitivity analyses.
Conclusions: Our evaluation found that memantine monotherapy produced relevant health benefit, compared with standard care alone, with no additional costs. Results are consistent with other economic evaluations of memantine conducted in Europe and the United States.