Figure 2. Summary estimates for the change in Alzheimer's Disease Assessment Scale–cognitive subscale (ADAS-cog) scores.

For donepezil (10 mg/d) versus placebo (Alzheimer disease [AD], all severity levels), the estimate was statistically significant (P < 0.001) and tests for heterogeneity were not significant (I² = 0.0%; P = 0.94). For donepezil (10 mg/d) versus placebo (mild cognitive impairment), the estimate was not significant (P = 0.31) and tests for heterogeneity were significant (I² = 75.5%; P = 0.043). For donepezil (10 mg/d) versus placebo (mild to moderate vascular dementia), the estimate was significant (P < 0.001) and tests for heterogeneity were not significant (I² = 0.0%; P = 0.84). For galantamine (24 mg) versus placebo (mild to moderate AD), the estimate was significant (P < 0.001) and tests for heterogeneity were significant (I² = 75.5%; P = 0.001). For galantamine (24 mg) versus placebo (mild to moderate AD and vascular dementia), the estimate was significant (P < 0.001). For rivastigmine (6 mg and 12 mg) versus placebo (AD, all severity levels), the estimate was significant (P < 0.001) and tests for heterogeneity were significant (I² = 90.8%; P < 0.001). For memantine (20 mg) versus placebo (mild to moderate AD), the estimate was not significant (P = 0.25). For memantine (20 mg) versus placebo (mild to moderate vascular dementia), the estimate was significant (P < 0.001) and tests for heterogeneity were not significant (I² = 11.4%; P = 0.29).