Anticholinergic burden for prediction of cognitive decline or neuropsychiatric symptoms in older adults with mild cognitive impairment or dementia

Anticholinergic deprescribing interventions for reducing risk of cognitive decline or dementia in older adults with and without prior cognitive impairment

BACKGROUND

Anticholinergics are medications that block the action of acetylcholine in the central or peripheral nervous system. Medications with anticholinergic properties are commonly prescribed to older adults. The cumulative anticholinergic effect of all the medications a person takes is referred to as the anticholinergic burden. A high anticholinergic burden may cause cognitive impairment in people who are otherwise cognitively healthy, or cause further cognitive decline in people with pre-existing cognitive problems. Reducing anticholinergic burden through deprescribing interventions may help to prevent onset of cognitive impairment or slow the rate of cognitive decline.

OBJECTIVES

Primary objective • To assess the efficacy and safety of anticholinergic medication reduction interventions for improving cognitive outcomes in cognitively healthy older adults and older adults with pre-existing cognitive issues. Secondary Objectives • To compare the effectiveness of different types of reduction interventions (e.g. pharmacist-led versus general practitioner-led, educational versus audit and feedback) for reducing overall anticholinergic burden. • To establish optimal duration of anticholinergic reduction interventions, sustainability, and lessons learnt for upscaling • To compare results according to differing anticholinergic scales used in medication reduction intervention trials • To assess the efficacy of anticholinergic medication reduction interventions for improving other clinical outcomes, including mortality, quality of life, clinical global impression, physical function, institutionalisation, falls, cardiovascular diseases, and neurobehavioral outcomes.

SEARCH METHODS

We searched CENTRAL on 22 December 2022, and we searched MEDLINE, Embase, and three other databases from inception to 1 November 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of interventions that aimed to reduce anticholinergic burden in older people and that investigated cognitive outcomes.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, extracted data, and assessed the risk of bias of included studies. The data were not suitable for meta-analysis, so we summarised them narratively. We used GRADE methods to rate our confidence in the review results.

MAIN RESULTS

We included three trials with a total of 299 participants. All three trials were conducted in a cognitively mixed population (some cognitively healthy participants, some participants with dementia). Outcomes were assessed after one to three months. One trial reported significantly improved performance on the Digit Symbol Substitution Test (DSST) in the intervention group (treatment difference 0.70, 95% confidence interval (CI) 0.11 to 1.30), although there was no difference between the groups in the proportion of participants with reduced anticholinergic burden. Two trials successfully reduced anticholinergic burden in the intervention group. Of these, one reported no significant difference between the intervention versus control in terms of their effect on cognitive performance measured by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) immediate recall (mean between-group difference 0.54, 95% CI -0.91 to 2.05), CERAD delayed recall (mean between-group difference -0.23, 95% CI-0.85 to 0.38), CERAD recognition (mean between-group difference 0.77, 95% CI -0.39 to 1.94), and Mini-Mental State Examination (mean between-group difference 0.39, 95% CI -0.96 to 1.75). The other trial reported a significant correlation between anticholinergic burden and a test of working memory after the intervention (which suggested reducing the burden improved performance), but reported no effect on multiple other cognitive measures. In GRADE terms, the results were of very low certainty. There were no reported between-group differences for any other clinical outcome we investigated. It was not possible to investigate differences according to type of reduction intervention or type of anticholinergic scale, to measure the sustainability of interventions, or to establish lessons learnt for upscaling. No trials investigated safety outcomes.

AUTHORS' CONCLUSIONS

There is insufficient evidence to reach any conclusions on the effects of anticholinergic burden reduction interventions on cognitive outcomes in older adults with or without prior cognitive impairment. The evidence from RCTs was of very low certainty so cannot support or refute the hypothesis that actively reducing or stopping prescription of medications with anticholinergic properties can improve cognitive outcomes in older people. There is no evidence from RCTs that anticholinergic burden reduction interventions improve other clinical outcomes such as mortality, quality of life, clinical global impression, physical function, institutionalisation, falls, cardiovascular diseases, or neurobehavioral outcomes. Larger RCTs investigating long-term outcomes are needed. Future RCTs should also investigate potential benefits of anticholinergic reduction interventions in cognitively healthy populations and cognitively impaired populations separately.

The Prognostic Utility of Anticholinergic Burden Scales: An Integrative Review and Gap Analysis

BACKGROUND

Anticholinergic drugs are commonly prescribed, especially to older adults. Anticholinergic burden scales (ABS) have been used to evaluate the cumulative effects of multiple anticholinergics. However, studies have shown inconsistent results regarding the association between anticholinergic burden assessed with ABS and adverse clinical outcomes such as cognitive impairment, functional decline, and frailty. This review aims to identify gaps in research on the development, validation, and evaluation of ABS, and provide recommendations for future studies.

METHOD

A comprehensive search of five databases (MEDLINE, Embase, PsychInfo, CINAHL, CENTRAL) was conducted for relevant studies published from inception until 25 May 2023. Two reviewers screened for eligibility and assessed the quality of studies using different tools based on the study design and stage of the review framework. Research evidence was evaluated, and gaps were identified and grouped into evidence, knowledge, and methodological gaps, using evidence tables to summarize data.

RESULTS

Several evidence, knowledge, and methodological gaps in existing development, validation, and evaluation studies of ABS were identified. There is no universally accepted scale, and there is a need to define a clinically relevant threshold for measuring total anticholinergic burden. The current evidence has limitations, underrepresenting low- and middle-income countries, younger individuals, and populations with cognitive disabilities. The impact of anticholinergic burden on frailty is also understudied. Existing evaluation studies provide limited evidence on the benefit of reducing anticholinergic burden on clinical outcomes or the safety of anticholinergic deprescribing. There is also uncertainty regarding optimal reduction, clinically significant anticholinergic burden thresholds, and cost effectiveness.

CONCLUSIONS

Future research recommendations to bridge knowledge gaps include developing a risk assessment framework, refining ABS scales, establishing a standardized consensus scale, and creating a longitudinal measure of cumulative anticholinergic risk. Strategies to minimize bias, consider frailty, and promote multidisciplinary and multinational collaborations are also necessary to improve patient outcomes.

Anticholinergic deprescribing interventions for reducing risk of cognitive decline or dementia in older adults with and without prior cognitive impairment

This is a protocol for a Cochrane Review (intervention). The objectives are as follows: