Influence of anticholinergic activity in serum on clinical symptoms of Alzheimer's disease

The neurocognition of dreaming: key questions and foci

Until recently, understanding the neurobiology of dreaming has relied upon on correlating a subjective dream report with a measure of brain activity or function sampled from a different occasion. As such, most assumptions about dreaming come from the neuroscience of rapid eye-movement (REM) sleep from which many, but not all, dream reports are recalled. Core features of REM sleep (intense emotional activation, a reduction in activity in most frontal regions, particularly the dorsolateral prefrontal cortex, along with increased dopamine, acetylcholine, cholinergic activation) align with typical dream characteristics (characterised by fear, reduced reality monitoring, increased bizarreness and hyperassociativity, respectively). The default mode network offers a way of understanding the nature of dreaming more independently from a REM sleep context, and electroencephalography methods paired with serial awakenings to elicit dream reports demonstrate how high-frequency activity in posterior regions may be associated with dreaming. Nevertheless, all measures of dreaming rely fundamentally on recall processes, so our understanding of dreaming must embrace and address memory's crucial involvement in dream report production.

Cholinergic Antagonists and Behavioral Disturbances in Neurodegenerative Diseases

Cholinergic antagonists interfere with synaptic transmission in the central nervous system and are involved in pathological processes in patients with neurocognitive disorders (NCD), such as behavioral and psychological symptoms of dementia (BPSD). In this commentary, we will briefly review the current knowledge on the impact of cholinergic burden on BPSD in persons with NCD, including the main pathophysiological mechanisms. Given the lack of clear consensus regarding symptomatic management of BPSD, special attention must be paid to this preventable, iatrogenic condition in patients with NCD, and de-prescription of cholinergic antagonists should be considered in patients with BPSD.

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.

Mini Review: Anticholinergic Activity as a Behavioral Pathology of Lewy Body Disease and Proposal of the Concept of "Anticholinergic Spectrum Disorders"

Given the relationship between anticholinergic activity (AA) and Alzheimer's disease (AD), we rereview our hypothesis of the endogenous appearance of AA in AD. Briefly, because acetylcholine (ACh) regulates not only cognitive function but also the inflammatory system, when ACh downregulation reaches a critical level, inflammation increases, triggering the appearance of cytokines with AA. Moreover, based on a case report of a patient with mild AD and slightly deteriorated ACh, we also speculate that AA can appear endogenously in Lewy body disease due to the dual action of the downregulation of ACh and hyperactivity of the hypothalamic-pituitary-adrenal axis. Based on these hypotheses, we consider AA to be a behavioral pathology of Lewy body disease. We also propose the concept of “anticholinergic spectrum disorders,” which encompass a variety of conditions, including AD, Lewy body disease, and delirium. Finally, we suggest the prescription of cholinesterase inhibitors to patients in this spectrum of disorders to abolish AA by upregulating ACh.

[Risk/benefit assessment in the treatment of Alzheimer's disease. Drug interactions]

INTRODUCTION

Anticholinergic drugs reduce the efficacy of acetylcholinesterase inhibitors (AChEI) and are inappropriate in elderly patients. The aim of this study is to determine the prevalence rate of prescription AChEI drugs and anticholinergics in a Healthcare Area, to identify the affected patients, and to inform the attending physicians, in order to evaluate the suitability of treatments.

MATERIAL AND METHODS

A descriptive cross-sectional observational study of prevalence. Patients on treatment with AChEI and any anticholinergic drug in the first quarter of 2015 were selected. The review of Duran et al. was used as reference to identify anticholinergics, assigning a score to each drug according to its anticholinergic potency. Physicians were provided with a report about the interaction, the list of affected patients, and recommendations.

RESULTS

A total of 486 patients were included in the study, representing 59.0% of total patients with Alzheimer's disease in the Area. There were 66.0% women, and 86.8% of the patients were older than 75 years, and with a mean of 9.2 drugs per patient. The mean number of anticholinergic drugs was 1.6, and 38.3% of patients were prescribed various anticholinergic drugs, with 23.9% on high potency anticholinergic drugs. A statistically significant association was found between taking an anticholinergic and AChEI concomitantly (P=.000; OR: 3.9).

CONCLUSIONS

The prevalence of interactions between AChEI and anticholinergic drugs is relevant, considering that it affects vulnerable members of the population. Providing physicians with information about the interaction could help them make clinical decisions, and could improve patient safety, as well as health outcomes.

Serum Anticholinergic Activity and Cognitive and Functional Adverse Outcomes in Older People: A Systematic Review and Meta-Analysis of the Literature

INTRODUCTION

Studies have reported associations between serum anticholinergic activity (SAA) and decline in cognitive performance, delirium, and functional impairment. The aim of this meta-analysis was to explore and quantify associations between SAA and adverse cognitive and functional outcomes in older people.

MATERIALS AND METHODS

A literature search in Ovid MEDLINE, EMBASE, PsycINFO and IPA from 1946-2014 was completed. The primary outcomes of interest were cognitive and functional adverse outcomes associated with SAA in older people aged 55 years and above. The Cochrane Risk-Bias assessment tool was used to assess bias in randomised controlled trials (RCTs). The Newcastle-Ottawa Scale was used to assess the quality of non-RCTs. Meta-analyses were conducted for RCTs and cohort studies separately. Heterogeneity was assessed using I2 tests.

RESULTS

The primary electronic literature search identified a total of 1559 records in the 4 different databases. On the basis of full-text analysis, 33 studies that met the inclusion criteria. The review included 4 RCTs, 5 prospective cohort studies, 3 longitudinal cohort studies, 17 cross-sectional studies, and 4 case-control studies. Twenty-four of the retrieved studies examined an association between SAA and cognitive outcomes, 2 studies examined an association with SAA and functional outcomes and 8 studies examined associations between SAA and both cognitive, and functional outcomes. The meta-analysis on 4 RCTs showed no association with higher SAA and cognitive performance (I2 = 89.38%, H2 = 25.53 and p-value = <0.05) however, the pooled data from 4 observational studies showed elevated SAA was associated with reduced cognitive performance (I2 = 0.00%, H2 = 3.37 and p-value = 0.34).

CONCLUSION

This systematic review summarises the limitations of the SAA on predicting cognitive and functional outcomes in older people. SAA measured by receptor bioassay is flawed and its use in older people with multimorbidity and polypharmacy is questionable.

Variants of Base Excision Repair Genes MUTYH , PARP1 and XRCC1 in Alzheimer's Disease Risk

BACKGROUND

Many clinical studies have shown that oxidative stress pathways and the efficiency of the oxidative DNA damage base excision repair (BER) system are associated with the pathogenesis of Alzheimer's disease (AD). Reduced BER efficiency may result from polymorphisms of BER-related genes. In the present study, we examine whether single nucleotide polymorphisms (SNPs) of BER genes are associated with increased risk of AD.

METHODS

SNP genotyping was carried out on DNA isolated from peripheral blood mononuclear cells obtained from 120 patients with AD and 110 healthy volunteers. Samples were genotyped for the presence of BER-related SNPs, i.e. XRCC1-rs1799782, rs25487; MUTYH-rs3219489, and PARP1-rs1136410.

RESULTS

We found a positive association between AD risk and the presence of G/A genotype variant of the XRCC1 rs25487 polymorphism [odds ratio (OR) = 3.762, 95% CI: 1.793-7.891]. The presence of the A/A genotype of this polymorphism reduced the risk of AD (OR = 0.485, 95% CI: 0.271-0.870). In cases of the PARP1 gene rs1136410 polymorphism, we observed that the T/C variant increases (OR = 4.159, 95% CI: 1.978-8.745) while the T/T variant reduces risk (OR = 0.240, 95% CI: 0.114-0.556) of AD.

CONCLUSIONS

We conclude that BER gene polymorphisms may play an important role in the etiology of AD. Diagnosing the presence or absence of particular genetic variants may be an important marker of AD. Further research on a larger population is needed. There is also a need to examine polymorphisms of other BER in the context of AD risk.

Does Anticholinergic Activity Affect Neuropathology? Implication of Neuroinflammation in Alzheimer's Disease

One characteristic neuropathological feature of Alzheimer's disease (AD) is profound neuronal loss in the nucleus basalis of Meynert, the major source of cholinergic innervation of the cerebral cortex. Clinically, anticholinergic activity causes a decline in cognitive function and increases the risk of dementia, thus possibly enhancing AD pathologies and neurodegeneration. Until now there has been insufficient human neuropathological data to support this conclusion. Experimental studies using a tauopathy mouse model demonstrated anticholinergics enhanced tau pathology and neurodegeneration corresponding to central anticholinergic activity. Additionally, donepezil, a cholinesterase inhibitor, ameliorated tau pathology and neurodegeneration in the same mouse model. These results indicate the balance between cholinergic and anticholinergic activities might affect neurodegeneration. Importantly, neurodegeneration observed in the mouse model seemed to correspond to the distribution of microglial activation, and it was reported that neuroinflammation plays an important role in the pathomechanism of AD, while anticholinergic activity augments inflammatory responses. Moreover, some studies indicated β-amyloid itself depletes cholinergic function similarly to anticholinergic activity. Thus, anticholinergic activity might initiate and/or accelerate AD pathology. Limited human data support the conclusion that anticholinergic activity enhances AD-related neuropathology and neurodegeneration. However, experimental data from a tauopathy mouse model indicated anticholinergic activity might enhance neurodegeneration with enhanced neuroinflammation including microglial activation.

Serum Anticholinergic Activity as an Index of Anticholinergic Activity Load in Alzheimer's Disease

We reported a procedure of serum anticholinergic activity (SAA) measurement and the reliability and reproducibility of the receptor binding assay, and we also described the usefulness of SAA measurement reflecting the anticholinergic activity (AA) in the central nervous system (CNS). According to the results of a 10 times repeated measurement of standard atropine binding, the relative error was between -5.5 and +3.7%, and we considered that measurement of SAA in our studies is accurate and validated. Downregulation of acetylcholine activates inflammation in both CNS and peripheral tissue, which causes AA in both sites. Therefore, changes of AA in the CNS link with SAA in the peripheral system even if a substance having AA does not penetrate through the blood-brain barrier. Then we redescribe issues that require attention in the measurement of SAA. It is generally defined that any SAA greater than the detection limit of a quantitative atropine equivalent level (≥1.95 nM in our study) is positive. According to previous studies, SAA is considered to be positive when its atropine equivalent is ≥1.95 nM and undetectable when this is <1.95 nM. Nevertheless, as a low SAA can act as AA in the CNS, we should assume that SAA might also be positive if its marker concentration is between 0 and 1.95 nM. In addition, SAA should be measured around 11 a.m. or somewhat later because of the diurnal rhythm of cortisol in humans.

Hypothesis of Endogenous Anticholinergic Activity in Alzheimer's Disease

In this article, we review and repropose our hypothesis of the endogenous appearance of anticholinergic activity (AA) in Alzheimer's disease (AD). First, we introduce our previous articles and speculate that, because acetylcholine (ACh) regulates both cognitive function and inflammation, downregulation of this neurotransmitter causes upregulation of the inflammatory system. AA then appears endogenously with the production of cytokines and the downregulation of ACh in AD. To support our hypothesis, we present a female AD patient whose AA was considered to occur endogenously through her AD pathology. Her serum anticholinergic activity (SAA) was positive at her first visit to our memory clinic, was negative at the 1-year and 2-year follow-up visits, and had become positive again by 3 years. We speculate that the initial positive SAA was related to her AD pathology plus mental stress, and that her SAA at 3 years was related to her AD pathology only. Consequently, we believe that 2 patterns of SAA positivity (and therefore AA) exist. One occurs when the downregulation of ACh reaches a critical level, and the other occurs with the addition of some other factor such as medication, induced illness or mental stress that causes AA to affect AD pathology. Finally, we consider the pharmacotherapy of AD based on the proposed hypothesis and conclude that cholinesterase inhibitors can be used to prevent rapid disease progression, whereas N-methyl-D-aspartate receptor antagonists should be reserved for the treatment of AD that is already in a stage of rapid progression. We also propose a staging schema for patients with AD.

Use of Medicines with Anticholinergic and Sedative Effect Before and After Initiation of Anti-Dementia Medications

BACKGROUND

People with dementia may be particularly sensitive to cognitive impairment induced by anticholinergic and sedative medicines.

OBJECTIVE

This study aimed to examine if utilisation of medicines with anticholinergic and sedative effects changed before and after initiation of anti-dementia therapy.

METHODS

A retrospective cohort study was conducted using Australian pharmacy claim data (Pharmaceutical Benefit Scheme). People with first (index) dispensing for a cholinesterase inhibitor or memantine between 1 January 2009 and 31 December 2010 who were aged 65 years or over at the time of initiation were included. The proportion who received sedatives or anticholinergics in the 6 months prior to and post initiation of anti-dementia therapy was determined.

RESULTS

The cohort included 24,110 patients, with over half aged 75-84 years. Overall, 30 % received any class of anticholinergic or sedative medicine for at least 1 month in the 6 months prior to initiation of anti-dementia agents, and 36 % post initiation. Some patients (6 %) ceased anticholinergics or sedatives post initiation even though they had them in the months prior. However, 12 % commenced therapy with anticholinergics or sedatives post anti-dementia therapy initiation even though they were naïve to them in the 6 months prior to therapy.

CONCLUSION

Medicines with anticholinergic or sedative effects were commonly dispensed in one-third of people with dementia. Prescribers need to consider a review of patients on anticholinergic therapy with cholinesterase inhibitors as the effectiveness of the cholinesterase therapy may be compromised.

Serum anticholinergic activity: a possible peripheral marker of the anticholinergic burden in the central nervous system in Alzheimer's disease

We review the utility of serum anticholinergic activity (SAA) as a peripheral marker of anticholinergic activity (AA) in the central nervous system (CAA). We hypothesize that the compensatory mechanisms of the cholinergic system do not contribute to SAA if their system is intact and that if central cholinergic system deteriorates alone in conditions such as Alzheimer's disease or Lewy body dementia, CAA and SAA are caused by way of hyperactivity of inflammatory system and SAA is a marker of the anticholinergic burden in CNS. Taking into account the diurnal variations in the plasma levels of corticosteroids, which are thought to affect SAA, it should be measured at noon or just afterward.

Can medication management review reduce anticholinergic burden (ACB) in the elderly? Encouraging results from a theoretical model

BACKGROUND

Review of recent journal articles and various relevant current textbooks provides strong evidence to show that anticholinergic burden is a material issue in frail and at-risk patients. This study assesses the anticholinergic burden in a group of patients in residential care facilities and then applies a theoretical intervention model. It is based on a scoring system known as the Anticholinergic Cognitive Burden (ACB) scale, and attempts to reduce the anticholinergic burden while maintaining therapeutic benefits.

METHODS

A database of 691 patients was analyzed for each individual's ACB based on the scale of scoring produced by groups of experts in the area. A theoretical intervention was then conducted using relevant, evidence-based practice guidelines for clinical therapeutics in Australia. The intervention had the aim of reducing the total ACB without affecting the apparent intended effectiveness of the prescribed therapy.

RESULTS

Of the 35% (n = 242) patients who score at least 1 point on the ACB, a reduction is achievable in 59% of the cases. In particular, the reduction from a clinically significant score of 3 or above to 2 or below for 49 of those patients is possible in 85% of the cases. Overall, this represents a reduction from 7.10% to 1.01% for the entire population. It is also found that of the 246,960 counts of items dispensed (both prescription and non-prescription) for these patients, 47,334 (or 19.2%) of these were of agents on the ACB scale.

CONCLUSIONS

The study found that it appears to be possible that the total ACB of a group of 691 patients can be significantly reduced.

Measures of anticholinergic drug exposure, serum anticholinergic activity, and all-cause postdischarge mortality in older hospitalized patients with hip fractures

OBJECTIVES

To assess possible associations between anticholinergic drug exposure and serum anticholinergic activity (SAA) and their capacities to predict all-cause mortality in older hospitalized patients.

SETTING

Academic medical center.

PARTICIPANTS AND MEASUREMENTS

Data on clinical characteristics, full medication exposure, SAA, and 4 anticholinergic drug scoring systems (ADSSs: Anticholinergic Risk Scale [ARS], Anticholinergic Drug Scale, Anticholinergic Burden scale, and anticholinergic component of the Drug Burden Index) were collected in 71 older hospitalized patients (age 84 ± 6 years) awaiting surgical repair after hip fractures.

RESULTS

The median (range) SAA was 2.8 (1.1-4.9) pmol/mL. Age (ρ = 0.25, p = 0.03), Katz Index of Independence in Activities of Daily Living score (ρ = 0.39, p = 0.001), in-hospital delirium (ρ = 0.29, p = 0.01), preadmission cognitive impairment (ρ = 0.31, p = 0.01), and the number of nonanticholinergic drugs (n-NA, ρ = -0.27, p = 0.02) were associated with SAA. No significant associations were detected between ADSSs and SAA. Cognitive impairment (β = 2.1, 95% confidence interval [CI]: 0.7 to 2.5, p = 0.005) and n-NA (β = -0.3, 95% CI: -0.5 to -0.03, p = 0.03) were independently associated with SAA. Cognitive impairment (hazard ratio [HR]: 6.7, 95% CI: 1.1 to 40.3, p = 0.04) and higher ARS scores (HR: 2.2, 95% CI: 1.2 to 3.7, p = 0.006) independently predicted 3-month mortality whereas in-hospital delirium (HR: 3.6, 95% CI: 1.3 to 10.3, p = 0.02), living at home (HR: 0.2, 95% CI: 0.0 to 0.9, p = 0.03), and length of hospital stay (HR: 1.1, 95% CI: 1.0 to 1.2, p = 0.004) independently predicted 1-year mortality after adjustment for age, gender, and Charlson comorbidity index.

CONCLUSIONS

Cognitive impairment and n-NA, but not ADSSs, are independently associated with SAA in older hospitalized patients. The ARS score, together with cognitive impairment, in-hospital delirium, place of residence, and length of hospital stay, predicts all-cause mortality in this group.

Expert-based drug lists to measure anticholinergic burden: similar names, different results

BACKGROUND

Scoring scales such as the Anticholinergic Drug Scale (ADS), the Anticholinergic Risk Scale (ARS), and the Anticholinergic Cognitive Burden Scale (ACB) provide an estimation of total anticholinergic burden. Not all the lists include the same drugs, and the points given for certain drugs differ among them. Whether these discrepancies present important differences in the estimation of anticholinergic burden for an individual patient is unknown. Therefore, the aim of this study is to assess agreement among the three scales.

METHOD

Anticholinergic burden was measured with the three scales in 83 patients aged ≥65 years in a medium- and long-stay psychiatric hospital. Subsequently, patients were categorized into three risk categories: low risk (0 points), medium risk (1-2 points) or high risk (3 or more points). The chance-corrected measures of agreement for the different scores were determined with the k-statistic (kappa).

RESULTS

Values for kappa were: 0.19 for Anticholinergic Risk Scale-Anticholinergic Drug Scale, 0.21 for ACB-Anticholinergic Drug Scale and 0.25 for Anticholinergic Risk Scale-ACB. The mean anticholinergic burden measured with ACB was 3.28.

CONCLUSIONS

There is poor agreement among the three scales. These lists cannot be directly applied to different settings in which drug availability differs substantially, and they require periodic updates. Anticholinergic burden in our setting (psychogeriatric inpatients) was particularly high.

Donepezil abolishes anticholinergic activity in a patient with amnesia

We report the case of a 74-year-old woman who presented with amnesia and positive serum anticholinergic activity (SAA), which disappeared after treatment with the cholinesterase inhibitor donepezil for 1 year. Her only other regular medications were topical glaucoma preparations. We suggest that mental stress, mild cognitive impairment and Alzheimer's disease pathology combined to generate SAA in this patient. We also consider that SAA may have subsequently become negative because of upregulation of acetylcholine production by donepezil, and because the patient's other medications and physical condition (including glaucoma) remained unchanged during the 1-year period.

Longitudinal assessment of serum anticholinergic activity in delirium of the elderly

BACKGROUND

Delirium, a frequently occurring, devastating disease, is often underdiagnosed, especially in dementia. Serum anticholinergic activity (SAA) was proposed as a disease marker as it may reflect delirium's important pathogenetic mechanism, cholinergic deficiency. We assessed the association of serum anticholinergic activity with delirium and its risk factors in a longitudinal study on elderly hip fracture patients.

METHOD

Consecutive elderly patients admitted for hip fracture surgery (n = 142) were assessed longitudinally for delirium, risk factors, and serum markers (IL-6, cortisol, and SAA). Using a sophisticated statistical design, we evaluated the association between SAA and delirium in general and with adjustments, but also the temporal course, including the events fracture, surgery, and potential delirium, individual confounders, and a propensity score.

RESULTS

Among elderly hip fracture patients 51% developed delirium, these showed more risk factors (p < 0.001), and complications (p < 0.05). Uncontrolled SAA levels (463 samples) were significantly higher in the delirium group (4.2 vs. 3.4 pmol/ml) and increased with delirium onset, but risk factors absorbed the effect. Using mixed-modeling we found a significant increase in SAA concentration (7.6% (95%CI 5.0-10.2, p < 0.001)) per day, which was modified by surgery and delirium, but this effect was confounded by cognitive impairment and IL-6 values. Confounder control by propensity scores resulted in a disappearance of delirium-induced SAA increase.

CONCLUSIONS

Delirium-predisposing factors are closely associated with changes in the temporal profile of serum anticholinergic activity and thus neutralize the previously documented association between higher SAA levels and delirium. An independent relationship of SAA to delirium presence is highly questionable.

Behavioral disturbance in dementia

Behavioral disturbances are frequently the most challenging manifestations of dementia and are exhibited in almost all people with dementia. Common behavioral disturbances can be grouped into four categories: mood disorders (e.g., depression, apathy, euphoria); sleep disorders (insomnia, hypersomnia, night-day reversal); psychotic symptoms (delusions and hallucinations); and agitation (e.g., pacing, wandering, sexual disinhibition, aggression). They are often persistent, greatly diminish quality of life of patients and their family caregivers, cause premature institutionalization, and pose a high economic burden on the patient, family, and society. Behavioral disturbances can be prevented and treated with a multifaceted approach that supports dignity and promotes comfort and quality of life of persons with dementia and their family members. Management involves prompt treatment of reversible factors and management of symptoms using primarily individualized nonpharmacological interventions. Pharmacological interventions need to be restricted to behavioral emergencies and for short-term treatment of behavioral disturbances that pose imminent danger to self or others.