Impact of anticholinergic discontinuation on cognitive outcomes in older people: a systematic review

Medicines with anticholinergic properties increase the risks of functional and cognitive decline, morbidity and mortality, institutionalization and length of hospital stay in older people. It is postulated that minimizing anticholinergic burden should result in improved short-term memory, confusion and delirium, and may improve the quality of life and daily functioning of older people.

The objective of this systematic review was to investigate the impact of discontinuing medicines with anticholinergic properties on cognitive outcomes in older people.

A comprehensive systematic search was performed to identify relevant studies, using Medline, Embase, International Pharmaceutical Abstracts (IPA), PsycINFO, the Cumulative Index to Nursing and Allied Health Literature (CINAHL) and the Cochrane Central Register of Controlled Trials, from 1946 to July 2013. The critical appraisal was performed by two independent reviewers, and the data were extracted onto standardized forms. The primary outcome of interest was evaluation of cognitive changes in older people after anticholinergic discontinuation, measured using cognitive assessment scales. Meta-analysis was not conducted, because of the heterogeneity of the study designs, interventions and outcome measures.

The primary electronic literature search identified a total of 475 records in the six different databases. On the basis of full-text analysis, only four studies met the inclusion criteria. The review found two randomized control trials and two prospective cohort studies that met the inclusion criteria. Only the cohort studies demonstrated improvement of cognitive performance after discontinuation of anticholinergic medicines.

The impact of anticholinergic discontinuation on cognitive function remains poorly researched and poorly understood. A larger sample size, longer duration of follow-up and better methods of assessing anticholinergic-induced cognitive impairment are warranted.