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Background: Agitation and aggression in Alzheimer's disease (AD) are amongst the most serious of neuropsychiatric symptoms, and contribute to poor outcomes and worse quality of life. Previous studies have suggested a benefit for memantine on agitation and aggression, but none have examined its efficacy in community-dwelling patients with significant agitation and aggression at baseline, utilizing these behaviors as a primary outcome measure., Methods: Patients with moderate-to-severe AD with Neuropsychiatric Inventory (NPI) total score ≥13 and NPI agitation/aggression score ≥1 were randomized to placebo or 20-mg memantine in a double-blind, 24-week trial. Co-primary outcome measures were behavior, measured by total NPI score, and cognition, using the Severe Impairment Battery (SIB). Secondary outcome measures included global assessment, function and other measures of behavior. This trial was registered as Clinicaltrials.gov: NCT00857649., Results: A total of 369 patients (average age = 75, average MMSE = 12) were randomized to placebo or memantine. The study was prematurely terminated due to recruitment problems. There were no statistically significant differences between memantine and placebo in mean change from baseline in NPI, SIB, or any of the secondary outcome measures. Behavior improved in both groups (total NPI change scores -3.90 ± 1.24 for memantine and -5.13 ± 1.23 for placebo). Memantine was generally well tolerated and patient retention in both treatment arms was good., Conclusions: The study failed to show the superiority of memantine in this sample of patients with moderate-to-severe AD with significant baseline agitation and aggression. Methodological limitations could have contributed to these results.

Background/aims: Global cognitive scales and meta-analyses thereof are used to appraise therapeutic efficacy over a broad range of disease severity. Clinically, however, different aspects of cognition change in different stages of disease., Methods: Calculation of effect sizes for single cognitive functions on treatment as assessed by the Alzheimer's Disease Assessment Scale (ADAS-cog), the Mini-Mental-Status Examination (MMSE), and the Severe Impairment Battery (SIB). In these scales, subdomains of 'cognition', e.g. memory and language, are represented in different proportions. To exemplify the analysis of 'cognition', we used original data of previously published clinical studies with memantine., Results: Depending on dementia severity and on the scale used, the effect size for memory varies between -0.44 and +0.34 and for language between -0.40 and +0.26., Conclusion: Beyond interstudy variance, effect sizes for treatment with antidementia drugs are subject to disease stage, instruments used, and interaction thereof. Therefore, clinical interpretation is necessary to appraise therapeutic efficacy in clinical studies and meta-analyses thereof when patients with different severity are included or different instruments are used. Alternatively, severity-adapted endpoints should be used for appraisal and meta-analysis of therapeutic efficacy., (Copyright © 2011 S. Karger AG, Basel.)