Alzheimer's: Rivastigmine improves cognition
Clinical Bottom Line
High dose rivastigmine improves cognitive and functional outcomes in patients with mild to moderate Alzheimer's disease.
Citation
Rosler M, Anand R, Cicin-Sain A, Gauthier S et al. Efficacy and safety of rivastigmine in patients with Alzheimer's Disease: international randomised controlled trial. BMJ 1999;318:633-40.
Purchasing Question
Should rivastigmine be considered in patients with Alzheimer's for improving quality of life and reducing carers' costs?
Search Terms
MEDLINE search using rivastigmine, AND Alzheimer* AND controlled trial.
The Study
Multicentre, double blind, randomised controlled trial of high and low dose rivastigmine vs. placebo in 725 patients with mild to moderate Alzheimer's Disease, with a 12 week lead in dosage period and 14 week follow-up, conducted in 45 centres in Europe and North America.
Patients were recruited by their GPs or directly from specialist centres. They were randomly allocated by computer to placebo, low or high dose drug, using identical type and number of dosage capsules. Patients were assessed at baseline and follow-up using the Cognitive subscale of the Alzheimer's disease assessment scale, the progressive deterioration scale, and clinician interviews. Analysis was conducted in three ways (intention-to-treat, last observation carried forward analysis and observed cases analysis). All patients were accounted for within the intention-to-treat analysis.
The Evidence
| Outcome | Time to Outcome | CER | EER | RBI | ABI | NNT (95% CI) |
|---|---|---|---|---|---|---|
| Beneficial outcome (improvement in cognition on Alzheimer's scale) | 26 weeks | 16% | 24% | 50% | 8% | 13 (7 to 113) |
Comments
- In this study, relative risk = RR (here, relative benefit) = 0.24/0.16 = 1.5
- Similar results were obtained from the other assessment instruments, but the overall clinical validity of the instruments was not clearly presented in the paper.
Appraised By
Anna Donald and Sam Vincent March 1999.
Expiry Date
March 2001