- The majority of patients participating in Alzheimer's disease studies used cholinesterase inhibitors (ChEIs) or memantine (Namenda), in addition to their assigned study treatment.
- Users had more rapid decline of cognition than nonusers.
Why this matters
- Concomitant use of these drugs could confound results.
- 33.4% of patients used ChEIs only, 5.3% used memantine only, and 34.0% used both.
- Annual rate of decline on the Alzheimer Disease Assessment Scale-cognitive subscale was faster for users of ChEIs and/or memantine vs nonusers:
- in studies overall (difference, 1.4 points/year; 95% CI, 0.1-2.7); and
- in randomized trials (difference, 1.5 points/year; 95% CI, 0.1-2.8).
- Difference in rate of decline:
- nonsignificant for patients using only ChEIs (difference, 0.9 points/year; 95% CI, −0.6 to 2.3); and
- significant for patients using memantine with or without ChEIs (difference, 2.0 points/year; 95% CI, 1.3-2.7).
- Meta-analysis: 10 collaborative studies with 2714 patients having dementia or mild cognitive impairment resulting from Alzheimer's disease, or normal cognition.
- Main outcome: change in Alzheimer Disease Assessment Scale-cognitive subscale score.
- Funding: NIH; Aging and Disability Resource Center; others.
- Reasons for use unknown.
- Potential effect of dropout of more severely affected patients.
- Most studies conducted in academic medical centers.