Economic evaluation of treatment options in patients with Alzheimer's disease: a systematic review of cost-effectiveness analyses.

INTRODUCTION: Alzheimer's disease (AD) is common among the elderly; it is responsible for 60-80% of all dementia cases. AD is characterized by cognitive decline, behavioural and psychological symptoms, and reductions in functioning and independence. Because of its progressive neurodegenerative nature and unknown aetiology, the burden of AD becomes increasingly significant in an aging population. Estimates indicate that 35.6 million people worldwide suffered from AD in 2010. By 2030 and 2050, this figure is predicted to increase to 65.7 million and 115.4 million, respectively. Costs will also rise along with the increase in the number of people diagnosed with AD. In 2010, the worldwide costs associated with dementia were estimated to be $US604 billion.
OBJECTIVE: The objective of this study was to conduct a systematic review of current publications dealing with the pharmacoeconomic factors associated with AD medications and to describe the decision-analytic models used to evaluate long-term outcomes.
METHODS: A systematic literature search was performed to identify articles published between 1 January 2007 and 15 July 2010. The search was also based on a previous systematic review, which included literature up to 2007. Articles were included if they were complete and original economic evaluations of AD and if they were comparative in nature. A quality assessment of the included publications was conducted and relevant information was extracted into tables.
RESULTS: Seven out of 2067 identified articles were included in this systematic review. Four articles evaluated treatment with donepezil, one with galantamine and two with memantine. The studies were conducted in America, Europe and Asia. Five different groups of medications were compared. The incremental cost-effectiveness ratios (ICERs) for the group of patients treated with donepezil versus no drug treatment ranged from a dominant value to 281, 416.13 euros per quality-adjusted life-year (QALY). Patients treated with donepezil versus placebo showed ICERs with a range from a dominant value (not specified) up to 20, 866.77 euros per QALY. Treatment with memantine in addition to donepezil versus treatment with donepezil alone showed an ICER range from a dominant value to 6818.33 euros per QALY. In comparison with the memantine treatment as an add-on therapy, the ICER of memantine monotherapy versus standard care (without cholinesterase inhibitors [CEIs]) ranged from a dominant value to 63, 087.20 euros per QALY. Finally, the economic evaluation of galantamine in comparison with usual care without any AD drugs showed ICERs ranging from 1894.70 euros to 6953 euros per QALY.
CONCLUSION: The seven identified publications included in this review indicate that treatment with CEIs or memantine seems to be reasonable in terms of clinical effects and costs for patients with AD. Depending on different hypotheses, assumptions and variables (e.g. time horizon, discount rates, initial number of patients in different states, etc.) in the sensitivity analyses, treatment with these drugs seems to be primarily a cost-effective strategy or even a cost-saving strategy. Nevertheless, the results generally are associated with a degree of uncertainty. The comparability of the results from the different economic evaluations is limited because of the different assumptions made.