Cost-effectiveness of memantine in community-based Alzheimer's disease patients: An adaptation in Spain

Several clinical trials have demonstrated the efficacy and safety of the NMDA antagonist memantine in moderately severe to severe Alzheimer's disease (AD) patients. A 28-week pharmacoeconomic study conducted in the US also showed a reduction of total healthcare costs and informal care compared to placebo. Long-term implications of memantine treatment were modelled in the UK and Finland and revealed reductions in dependency, institutionalization and costs. However, these conclusions were not directly applicable to the Spanish setting where patients are mainly treated within the community. The objective of this study was to estimate the long-term implications in terms of costs and health benefits of memantine therapy compared to standard care using a Spanish adaptation of previous models over a 2-year time horizon. As in previous adaptations, Markov health states were defined as a combination of severity (mild-moderate, moderately severe, severe) and dependency plus death as the absorbing state. Spain-specific data (costs, mortality and epidemiological data) were obtained from local and recently published cohorts of AD patients. Data on the effectiveness of memantine were derived from a randomized double-blind placebo-controlled clinical trial of 252 moderately severe to severe AD patients. Effectiveness was measured as the time spent in a non-dependent health state. The evaluation was conducted over 2 years, while the efficacy of memantine was applied for 1 year only in order to ensure a conservative approach. The robustness of the model was tested by conducting stochastic analyses and various sensitivity analyses on the key assumptions. Patients receiving standard care were estimated to spend 6 months in a non-dependent state and to incur average total costs of Euro 24,700 over 2 years. The memantine strategy was associated with an additional 2.5 months in a non-dependent state and a Euro 700 cost reduction. Monte-Carlo simulations and sensitivity analyses supported these findings. Memantine appears to be cost-effective compared with standard care in moderately severe to severe AD patients in a Spanish setting. The prolonged independence provided by memantine treatment translated into cost reductions which offset drug costs and resulted in overall cost-savings.