Antonanzas Fernando, Rive Benoit, Badenas Josep M, Gomez-Lus Susana, Guilhaume Chantal
Department of Economics, Universidad de la Rioja, Logrono, Spain.
Eur J Health Econ. 2006 Jun;7(2):137-44. doi: 10.1007/s10198-006-0355-0.
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.
多项临床试验已证明N-甲基-D-天冬氨酸（NMDA）拮抗剂美金刚对中度至重度阿尔茨海默病（AD）患者的有效性和安全性。在美国进行的一项为期28周的药物经济学研究还表明，与安慰剂相比，美金刚可降低总体医疗成本和非正式护理成本。在英国和芬兰对美金刚治疗的长期影响进行了建模，结果显示其可降低患者的依赖性、机构化程度及成本。然而，这些结论并不直接适用于西班牙的情况，因为西班牙患者主要在社区接受治疗。本研究的目的是通过对先前模型进行西班牙化改编，在两年时间范围内估计与标准护理相比，美金刚治疗在成本和健康效益方面的长期影响。与先前的改编一样，马尔可夫健康状态被定义为严重程度（轻度 - 中度、中度严重、重度）与依赖性的组合，死亡作为吸收状态。西班牙的特定数据（成本、死亡率和流行病学数据）来自当地及近期发表的AD患者队列。美金刚有效性的数据来自一项针对252名中度至重度AD患者的随机双盲安慰剂对照临床试验。有效性以处于非依赖健康状态的时间来衡量。评估为期2年，而美金刚的疗效仅应用1年，以确保采用保守方法。通过对关键假设进行随机分析和各种敏感性分析来检验模型的稳健性。接受标准护理的患者预计在非依赖状态下花费6个月，两年内平均总费用为24,700欧元。美金刚治疗策略可使患者在非依赖状态下额外增加2.5个月，成本降低700欧元。蒙特卡洛模拟和敏感性分析支持了这些结果。在西班牙的情况下，对于中度至重度AD患者，与标准护理相比，美金刚似乎具有成本效益。美金刚治疗带来的更长时间的独立转化为成本降低，抵消了药物成本并实现了总体成本节约。
