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 li terature 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 (197 4-1998) 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 subs cale), Clinician's Interview Based Impression of Change Plus, Mini Mental S tate 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 symp toms, or postpone deterioration in one of them. Conclusions. These small NNTs suggest that, despite their expense, the chol inesterase inhibitors have a valuable place in the current clinical managem ent of AD. Copyright (C) 2000 John Wiley & Sons, Ltd.