Authors' objectives: The aim of this report is to assess: - Which agents demonstrate the best clinical efficacy in the treatment of Alzheimer's disease (AD)? - How reliable are the outcome measures (i.e. assessment scales) used to determine clinical efficacy of these agents? - What is the cost-effectiveness of agents currently approved for the treatment of AD in Canada?

Authors' recommendations: 1. Twenty-six randomized controlled trials of nine treatments or potential treatments retrieved from the literature were found to meet appropriate methodological standards. Although donepezil, metrifonate and rivastigmine all provided modest, measured differences in patients with probable mild to moderate AD, none of these therapies has been shown to stop the progression of the disease and none provided a clinically meaningful improvement in the majority of patients. 2. The results from the trials of Gingko biloba suggest smaller effects than those from the above mentioned therapies. It was concluded that for selegiline, vitamin E, lecithin, linopirdine and propentofylline, the published data do not provide support for efficacy. 3. All of these medications appear to be well tolerated with few adverse events. However, dropout rates were sometimes high and therefore apparent treatment effects may be overestimated. 4. There is evidence that many of the scales used to measure efficacy (outcome measures) are valid and reliable, although there was no clear evidence in favor of any one particular scale. Small sample sizes and inappropriate measures of correlation were sometimes used to assess these two properties. Also, responsiveness to change has generally not been adequately investigated. For these reasons, the clinical significance of the treatment versus placebo differences in some clinical trials remains unclear. 5. Economic analyses of donepezil and rivastigmine demonstrate either a slight increase or slight decrease in overall costs for patients with probable mild to moderate AD. All conclusions were based on modeling short-term efficacy data and are speculative. Long-term prospective studies will be required to validate the results from these models.

Authors' methods: Review

Project Status: Completed

URL for project: https://www.ccohta.ca/

Year Published: 1999

URL for published report: n/a

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: Canada

Organisation Name: Canadian Coordinating Office for Health Technology Assessment

Contact Address: 600-865 Carling Avenue, Ottawa, ON K1S 5S8 Canada. Tel: +1 613 226 2553, Fax: +1 613 226 5392;

Contact Name: requests@cadth.ca

Contact Email: requests@cadth.ca

Copyright: Canadian Coordinating Office for Health Technology Assessment