How useful are cholinesterase inhibitors in the treatment of Alzheimer's disease? A number needed to treat analysis.

Objectives To report on a Numbers Needed to Treat (NNT) analysis of the literature identified through a systematic review of trials of cholinesterase inhibitors in Alzheimer's Disease. Design Search of Medline (1966–1998), EMBASE (1994–1999) and Psychlit (1974–1998) using the keywords cholinesterase and placebo dementia. Settings Double-blind, randomised, placebo-controlled trials. Subjects People with Alzheimer's Disease. Interventions Drug trials of acetylcholinesterase inhibitors (ChIs). Main outcome measures Alzheimer's Disease Assessment Scale (Cognitive subscale), Clinician's Interview Based Impression of Change Plus, Mini Mental State Examination, Progressive Deterioration Scale. Results Small numbers of patients (in most cases between 3 and 7) need to be treated with appropriate dosages of ChIs to ameliorate the clinical symptoms, or postpone deterioration in one of them. Conclusions These small NNTs suggest that, despite their expense, the cholinesterase inhibitors have a valuable place in the current clinical management of AD. Copyright © 2000 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]