Exposure to Strong Anticholinergic Medications and Dementia-Related Neuropathology in a Community-Based Autopsy Cohort

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.

Beauty of the beast: anticholinergic tropane alkaloids in therapeutics

Tropane alkaloids (TAs) are among the most valued chemical compounds known since pre-historic times. Poisonous plants from Solanaceae family (Hyoscyamus niger, Datura, Atropa belladonna, Scopolia lurida, Mandragora officinarum, Duboisia) and Erythroxylaceae (Erythroxylum coca) are rich sources of tropane alkaloids. These compounds possess the anticholinergic properties as they could block the neurotransmitter acetylcholine action in the central and peripheral nervous system by binding at either muscarinic and/or nicotinic receptors. Hence, they are of great clinical importance and are used as antiemetics, anesthetics, antispasmodics, bronchodilator and mydriatics. They also serve as the lead compounds to generate more effective drugs. Due to the important pharmacological action they are listed in the WHO list of essential medicines and are available in market with FDA approval. However, being anticholinergic in action, TA medication are under the suspicion of causing dementia and cognitive decline like other medications with anticholinergic action, interestingly which is incorrect. There are published reviews on chemistry, biosynthesis, pharmacology, safety concerns, biotechnological aspects of TAs but the detailed information on anticholinergic mechanism of action, clinical pharmacology, FDA approval and anticholinergic burden is lacking. Hence the present review tries to fill this lacuna by critically summarizing and discussing the above mentioned aspects.

Inverse association between the anticholinergic burden and hippocampus volume in a population-based cohort across the entire adult age range

Many medications of different indications have a relevant anticholinergic activity. The anticholinergic burden of medication has been shown to have significant effects on the cognition and the risk for cognitive impairment and dementia particularly in older patients. So far, most of the studies used data from geriatric patients and the effect of the anticholinergic burden on brain structures is still unexplored. Our study aimed to analyze possible associations of hippocampus and cholinergic basal forebrain volumes as vulnerable brain structures for the development of dementia and the anticholinergic burden in a population-based cohort of non-demented participants spanning the adult age range from 21 to 80 years. We analyzed associations between medication-related anticholinergic burden and structural MRI volumes from participants (n = 3087, 52.2% female) of the population-based “Study of Health in Pomerania” (SHIP). Anticholinergic burden was obtained from the current medication plan using the Anticholinergic Burden Scale (ACB). All analyses were adjusted for age, sex, education, and total intracranial volume. We found statistically significant associations between the ACB and the left and right hippocampus volume but not for the basal forebrain cholinergic system. Complementary voxel-based analysis across all participants revealed FWE-corrected (p =  < 0.05) clusters in the temporo-parietal regions reaching into frontal areas, showing reduced volumes with higher ACB scores. We identified an association between anticholinergic burden of medication on hippocampal volume suggesting a potential inverse effect of such medication. This association highlights the importance of a careful prescription of medication with anticholinergic activity at any adult age.

The cognitive effect of anticholinergics for patients with overactive bladder

Overactive bladder (OAB) is often treated with medications that block the cholinergic receptors in the bladder (known as anticholinergics). The effect of this medication class on cognition and risk of dementia has been increasingly studied over the past 40 years after initial studies suggested that the anticholinergic medication class could affect memory. Short-term randomized clinical trials demonstrated that the administration of the anticholinergic oxybutynin leads to impaired memory and attention, and large, population-based studies showed associations between several different anticholinergic medications and dementia. However, trials involving anticholinergics other than oxybutynin have not shown such substantial effects on short-term cognitive function. This discordance in results between short-term cognitive safety of OAB anticholinergics and the long-term increased dementia risk could be explained by the high proportion of patients using oxybutynin in the OAB subgroups of the dementia studies, or a study duration that was too short in the prospective clinical trials on cognition with other OAB anticholinergics. Notably, all studies must be interpreted in the context of potential confounding factors, such as when prodromal urinary symptoms associated with the early stages of dementia lead to an increase in OAB medication use, rather than the use of OAB medication causing dementia. In patients with potential risk factors for cognitive impairment, the cautious use of selected OAB anticholinergic agents with favourable physicochemical and pharmacokinetic properties and clinical trial evidence of cognitive safety might be appropriate.

The treatment of neurogenic lower urinary tract dysfunction in persons with spinal cord injury: An open label, pilot study of anticholinergic agent vs. mirabegron to evaluate cognitive impact and efficacy

STUDY DESIGN

Pre-post intervention.

OBJECTIVES

1. To test whether replacement of oral anticholinergic (AC) agents with mirabegron for neurogenic lower urinary tract dysfunction (NLUTD) yields improved cognitive function in older persons with spinal cord injury (SCI). 2. To test whether mirabegron is safe and as efficacious as AC.

SETTING

USA.

METHODS

Pilot study: Twenty older (>60 y/o) persons with SCI taking chronic (>6 months) AC medication for NLUTD were enrolled. All participants were first studied on AC at baseline then switched to mirabegron for 6 months. Primary outcomes were cognitive tests of (1) executive function (TEXAS, SDMT); (2) attention (SCWT); and (3) memory (SLUMS and WMS-IV Story A/B). Secondary outcomes assessed efficacy and safety including Neurogenic Bladder Symptom Score (NBSS), bladder diary, neurogenic bowel dysfunction (NBD) survey, heart rate (HR), electrocardiogram (EKG), and mean arterial pressure (MAP).

RESULTS

When switching from AC to mirabegron for NLUTD, older persons with SCI exhibited statistically significant improvements in immediate Story A recall (p = 0.01), delayed story A and B recall (p = 0.01, 0.004), and in TEXAS (p = 0.04). Three subscores within NBSS significantly improved (p = 0.001) and the frequency of incontinence decreased (p = 0.03) on mirabegron. NBD, HR, MAP, and EKGs were unchanged.

CONCLUSIONS

Older persons with SCI on AC for NLUTD demonstrated improved short-term and delayed memory (WMS-IV Story A/B) as well as executive function (TEXAS) when switched to mirabegron. Efficacy of mirabegron for NLUTD symptoms was superior to AC with no adverse effects on bowel or cardiovascular function.

SPONSORSHIP

Claude D. Pepper Older Americans Independence Center.

Anticholinergic drugs and the risk of dementia: A systematic review and meta-analysis

Dementia is one of the greatest global challenges for public health; however, the relationship between anticholinergic drugs and dementia remains unclear. The aim of the present study was to perform a systematic review and meta-analysis of the predictive roles of anticholinergic drugs in dementia risk. After pooling fourteen longitudinal and case-control studies with a total of 1,564,181 subjects, anticholinergic drug use was associated with an increased risk of all-cause dementia and Alzheimer's disease. Both low and high anticholinergic drug burdens were associated with dementia. Moreover, there was a dose-dependent relationship between anticholinergic drugs and risk of dementia. With respect to the categories of anticholinergic drugs, antiparkinson, urological drugs, and antidepressants increased the risk for dementia; however, cardiovascular and gastrointestinal drugs played potentially protective roles. These findings underscore the importance of anticholinergic drugs as a potential modifiable risk factor for dementia and provide treatment priorities to optimize dementia prevention.

Neuropathological Correlates of Cumulative Benzodiazepine and Anticholinergic Drug Use

BACKGROUND

Benzodiazepines and anticholinergic drugs have been implicated in causing cognitive decline and potentially increasing dementia risk. However, evidence for an association with neuropathology is limited.

OBJECTIVE

To estimate the correlation between neuropathology at death and prior use of benzodiazepines and anticholinergic drugs.

METHODS

We categorized 298 brain donors from the population-based Medical Research Council Cognitive Function and Ageing Study, according to their history of benzodiazepine (including Z-drugs) or anticholinergic medication (drugs scoring 3 on the Anticholinergic Cognitive Burden scale) use. We used logistic regression to compare dichotomized neuropathological features for those with and without history of benzodiazepine and anticholinergic drug use before dementia, adjusted for confounders.

RESULTS

Forty-nine (16%) and 51 (17%) participants reported benzodiazepine and anticholinergic drug use. Alzheimer's disease neuropathologic change was similar whether or not exposed to either drug, for example 46% and 57% had intermediate/high levels among those with and without anticholinergic drug use. Although not significant after multiple testing adjustments, we estimated an odds ratio (OR) of 0.40 (95% confidence interval [95% CI] 0.18-0.87) for anticholinergic use and cortical atrophy. For benzodiazepine use, we estimated ORs of 4.63 (1.11-19.24) and 3.30 (1.02-10.68) for neuronal loss in the nucleus basalis and substantial nigra. There was evidence of neuronal loss in the nucleus basalis with anticholinergic drug use, but the association reduced when adjusted for confounders.

CONCLUSIONS

We found no evidence that benzodiazepine or anticholinergic drug use is associated with typical pathological features of Alzheimer's disease; however, we cannot rule out effects owing to small numbers.

Fine Particulate Matter and Markers of Alzheimer's Disease Neuropathology at Autopsy in a Community-Based Cohort

BACKGROUND

Evidence links fine particulate matter (PM2.5) to Alzheimer's disease (AD), but no community-based prospective cohort studies in older adults have evaluated the association between long-term exposure to PM2.5 and markers of AD neuropathology at autopsy.

OBJECTIVE

Using a well-established autopsy cohort and new spatiotemporal predictions of air pollution, we evaluated associations of 10-year PM2.5 exposure prior to death with Braak stage, Consortium to Establish a Registry for AD (CERAD) score, and combined AD neuropathologic change (ABC score).

METHODS

We used autopsy specimens (N = 832) from the Adult Changes in Thought (ACT) study, with enrollment ongoing since 1994. We assigned long-term exposure at residential address based on two-week average concentrations from a newly developed spatiotemporal model. To account for potential selection bias, we conducted inverse probability weighting. Adjusting for covariates with tiered models, we performed ordinal regression for Braak and CERAD and logistic regression for dichotomized ABC score.

RESULTS

10-year average (SD) PM2.5 from death across the autopsy cohort was 8.2 (1.9) μg/m3. Average age (SD) at death was 89 (7) years. Each 1μg/m3 increase in 10-year average PM2.5 prior to death was associated with a suggestive increase in the odds of worse neuropathology as indicated by CERAD score (OR: 1.35 (0.90, 1.90)) but a suggestive decreased odds of neuropathology as defined by the ABC score (OR: 0.79 (0.49, 1.19)). There was no association with Braak stage (OR: 0.99 (0.64, 1.47)).

CONCLUSION

We report inconclusive associations between PM2.5 and AD neuropathology at autopsy among a cohort where 94% of individuals experienced 10-year exposures below the current EPA standard. Prior studies of AD risk factors and AD neuropathology are similarly inconclusive, suggesting alternative mechanistic pathways for disease or residual confounding.

Anticholinergic medications and risk of dementia in older adults: Where are we now?

INTRODUCTION

Anticholinergic medications are effective for a wide variety of indications, but are associated with significant central adverse effects, especially cognitive decline and dementia in older adults.

AREAS COVERED

We conducted a review of relevant literature in the past decade to address anticholinergic scales and evidence of anticholinergic-related dementia/cognitive decline in older adults. We discussed various anticholinergic scales used to classify anticholinergic medications. The review focused on the evidence from previous reviews and individual studies evaluating the anticholinergic-related risk of developing cognitive decline/dementia. This review also discussed clinical and methodological issues of studies along with recommendations for practice and research.

EXPERT OPINION

The review demonstrates moderate to strong risk of dementia with anticholinergic use in multiple studies involving older adults, irrespective of the study design, analytical approach, anticholinergic exposure and outcome definition. This risk is particularly significant with the cumulative burden and high-level anticholinergics. There also exists a dose-response relationship between anticholinergic use and increased risk for dementia. Therefore, anticholinergic agents can be considered as a modifiable risk factor for dementia and cognitive decline in older adults. Based on the current evidence, regular assessment and optimization of anticholinergic burden prior to prescribing these medications can minimize anticholinergic-related morbidity in older adults.

Anticholinergic Drugs in Geriatric Psychopharmacology

Drugs with anticholinergic action are widely prescribed in the elderly population due to their potential clinical benefits. However, these benefits are limited by adverse effects which may be serious in particular circumstances. This review presents different aspects of the use of anticholinergics in old age with a focus in psychogeriatric patients. We critically review published data on benefits and disadvantages of anticholinergics, which are often controversial. Prevalence, pathophysiology and measurement methods of the anticholinergic action of drugs are discussed. We also present the most important drawbacks resulting from its use, including effects on cognition in healthy and cognitively impaired people, in aged schizophrenia patients, emergence of delirium and psychiatric symptoms, influence in functionality, hospitalization, institutionalization and mortality, and the potential benefits and limitations of their discontinuation. Finally, we suggest practical recommendations for the safe use of anticholinergics in clinical conditions affecting elderly patients, such as dementia, schizophrenia and acute hallucinatory episodes, depression, anxiety, Parkinson's disease, cardiovascular conditions and urinary incontinence.

Is Ongoing Anticholinergic Burden Associated With Greater Cognitive Decline and Dementia Severity in Mild to Moderate Alzheimer’s Disease?

Background

Use of anticholinergic medication is associated with an increased risk of cognitive impairment and/or dementia. Despite this, the impact of continuing medication with anticholinergic properties in those diagnosed with Alzheimer’s Disease (AD) is not clear.

Methods

Analysis of data from NILVAD, an 18-month randomized controlled trial of Nilvadipine in AD. Effects of ongoing Anticholinergic Cognitive Burden (ACB) on cognition (ADAS-Cog: Alzheimer’s Disease Cog Subsection) and dementia severity (CDR-sb: Clinical Dementia Rating – Sum of Boxes/DAD: Disability Assessment for Dementia) over 18 months was evaluated adjusting for important clinical covariates.

Results

Just over one-quarter (27.90%, n = 142/510) of patients with mild to moderate AD were prescribed a potential/definite anticholinergic. While ACB score was not associated with greater progression on the ADAS-Cog/CDR-sb over time, a higher total ACB predicted greater dementia severity on the DAD, which persisted after robust covariate adjustment (β Coef: −1.53, 95% CI: −2.83 to −0.23, p = .021). There was a significant interaction between APOE ε4 status and ACB score, with carriers experiencing greater progression on both the CDR-Sb (β Coef: 0.36, 95% CI: 0.05–0.67, p = .021) and DAD (β Coef: −3.84, 95% CI: −7.65 to 0.03, p = .049).

Conclusions

Ongoing use of anticholinergic medication was associated with greater dementia progression on the DAD, but not the CDR-sb. APOE ε 4 carriers may be particularly vulnerable to the effect of ongoing anticholinergic medication on dementia severity, with significant APOE ε 4 x ACB score interactions demonstrated on both the DAD and CDR-sb.