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

Development and Pilot Testing of an Algorithm-Based Approach to Anticholinergic Deprescribing in Older Patients

BACKGROUND

Adverse anticholinergic drug reactions are common, yet evidence on how to reduce exposure to anticholinergic activity and reliably measure successful deprescribing is still scant. This study proposes an algorithm-based approach to evaluate and reduce anticholinergic load, and reports the results of its pilot testing.

METHODS

Based on published evidence and expert opinion, a list of 85 anticholinergic drugs and 21 algorithms for reducing anticholinergic load, e.g., by recommending alternative drugs with lower risk, were developed. An accompanying test battery was assembled by focusing on instruments that sensitively reflect anticholinergic load and may be sensitive to depict changes (Neuropsychological Assessment Battery to measure memory and attention, validated assessments for constipation, urinary symptoms, and xerostomia, as well as blood biomarkers). The approach was pilot-tested in a geriatric rehabilitation unit, with clinician feedback as the primary outcome and characterization of anticholinergic symptoms as the secondary outcome. The intervention was delivered by a pharmacist and a clinical pharmacologist who used the algorithms to generate personalized recommendation letters.

RESULTS

We included a total of 20 patients, 13 with anticholinergic drugs and 7 without. Recommendations were made for 22 drugs in nine patients from the intervention group, of which seven letters (78%) were considered helpful and 8/22 (36%) anticholinergic drugs were discontinued, reducing anticholinergic load in seven patients. In contrast to patients without drug change, memory assessment in patients with reduced anticholinergic load improved significantly after 2 weeks (6 ± 3 vs. -1 ± 6 points).

CONCLUSIONS

The approach was well received by the participating physicians and might support standardized anticholinergic deprescribing.

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.

Are Anticholinergic Medications Associated With Increased Risk of Dementia and Behavioral and Psychological Symptoms of Dementia? A Nationwide 15-Year Follow-Up Cohort Study in Taiwan

BACKGROUND/OBJECTIVE

In previous reports, the usage of anticholinergic medications has been associated with an increased risk of dementia with prolonged usage or with a high Anticholinergic Cognitive Burden (ACB). This study aimed to investigate the association between anticholinergic medications and the risk of dementia using data from Taiwan's National Health Research Database (NHIRD).

METHODS

A total of 790,240 patients, with 197,560 patients receiving anticholinergic medications and 592,680 control patients (1:3) matched for sex, age, and index-year, were enrolled from the two million Longitudinal Health Insurance Dataset, a subdataset of the NHIRD, between 2000 and 2015. The time-dependent Cox regression analysis was used to explore the hazard ratio (HR) with a 95% confidence interval for the association between anticholinergics and the risk of dementia during the 15-year follow-up. The behavioral and psychological symptoms of dementia (BPSD) were recognized by the usage of psychotropics. The ACB ranged from zero to three, divided as score <1, 1-1.9, 2-2.9, 3-4.9,and ≧5. The sensitivity analysis was done by excluding the diagnoses of dementia in the first 2 or 4 years after anticholinergic usage.

RESULTS

In the anticholinergic usage cohort, the HR was 1.043 (95% CI = 0.958-1.212, p = 0.139) without a significant difference. The sensitivity analysis revealed no association between the usage of anticholinergics and the risk of dementia. Anticholinergic usage was not associated with BPSD. Male sex, patients of ages of 60-64 and ≧80, usage of antiparkinsonian medications, a history of Parkinson's disease, epilepsy, urinary incontinence, depression, bipolar disorder, and psychotic disorder were independent risk factors of dementia. Increased HRs for dementia were associated with an ACB ≥ 5 and an anticholinergic usage period ≥ 1,460 days.

CONCLUSION

In this study, the usage of anticholinergics was not associated with the risk of dementia or BPSD in a 15-year follow-up study. However, patients with the male sex, patients with ages of 65-79 and ≧80, patients with some comorbidities, high ACB scores, and long anticholinergic treatment duration were associated with the risk of dementia.

Anticholinergic burden in schizophrenia and ability to benefit from psychosocial treatment programmes: a 3-year prospective cohort study

BACKGROUND

Many medications administered to patients with schizophrenia possess anticholinergic properties. When aggregated, pharmacological treatments may result in a considerable anticholinergic burden. The extent to which anticholinergic burden has a deleterious effect on cognition and impairs ability to participate in and benefit from psychosocial treatments is unknown.

METHOD

Seventy patients were followed for approximately 3 years. The MATRICS consensus cognitive battery (MCCB) was administered at baseline. Anticholinergic burden was measured with the Anticholinergic Cognitive Burden (ACB) scale. Ability to benefit from psychosocial programmes was measured using the DUNDRUM-3 Programme Completion Scale (D-3) at baseline and follow-up. Psychiatric symptoms were measured using the PANSS. Total antipsychotic dose was measured using chlorpromazine equivalents. Functioning was measured using the Social and Occupational Functioning Assessment Scale (SOFAS).

RESULTS

Mediation analysis found that the influence of anticholinergic burden on ability to participate and benefit from psychosocial programmes was completely mediated by the MCCB. For every 1-unit increase on the ACB scale, change scores for DUNDRUM-3 decreased by -0.27 points. This relationship appears specific to anticholinergic burden and not total antipsychotic dose. Moreover, mediation appears to be specific to cognition and not psychopathology. Baseline functioning also acted as mediator but only when MCCB was not controlled for.

CONCLUSIONS

Anticholinergic burden has a significant impact on patients' ability to participate in and benefit from psychosocial treatment programmes. Physicians need to be mindful of the cumulative effect that medications can have on patient cognition, functional capacity and ability to benefit from psychosocial treatments.

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.

Anticholinergic Activity and Schizophrenia

In this article, we review the downregulation of acetylcholinergic activity in schizophrenia and discuss the similarity and difference between Alzheimer's disease (AD) and schizophrenia in terms of acetylcholine (ACh) and anticholinergic activity (AA); then, we propose the use of cognition-enhancing therapy for schizophrenia. As ACh regulates an inflammatory system, when the cholinergic system is downregulated to a critical level, the inflammatory system is activated. We consider the possibility that AA appears endogenously in AD and accelerates AD pathology. This hypothesis can also be applied to schizophrenia. In fact, even before the onset of the disorder, in the prodromal phase of schizophrenia, cognitive dysfunction exists, and antibodies against astrocyte muscarinic-1 and muscarinic-2 receptors are present in the serum of patients with the paranoid type of schizophrenia. Then we noted that the prodromal phase in schizophrenia might correspond to the mild stage in AD and the acute phase to moderate stage concerning AA. We also think that we should enhance cognition in schizophrenia even in the prodromal phase because as mentioned above, downregulation of ACh is prominent in schizophrenia even in the prodromal phase.

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.

A Review of the Role of Anticholinergic Activity in Lewy Body Disease and Delirium

We have previously proposed a hypothesis in which we argue that anticholinergic activity (AA) appears endogenously in Alzheimer's disease (AD). Acetylcholine (ACh) controls both cognitive function and inflammation. Consequently, when the downregulation of ACh reaches critical levels, the inflammatory system is upregulated and proinflammatory cytokines with AA appear. However, factors other than downregulation of ACh can produce AA; even if ACh downregulation does not reach critical levels, AA can still appear if one of these other AA-producing factors is added. These factors can include neurocognitive disorders other than AD, such as delirium and Lewy body disease (LBD). In delirium, ACh downregulation fails to reach critical levels, but AA appears due to the use of medicines, physical illnesses or mental stress (termed 'AA inserts'). In LBD, we speculate that AA appears endogenously, even in the absence of severe cognitive dysfunction, for 2 reasons. One reason is that patterns of ACh deterioration are different in LBD from those in AD, with synergistic actions between amyloid and α-synuclein thought to cause additional or severe symptoms that accelerate the disease course. The second reason is that AA occurs through disinhibition by reduced cortisol levels that result from severe autonomic parasympathetic dysfunction in LBD.

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.

Demonstrating the Role of Anticholinergic Activity in a Mood Disorder

We report a case of a 54-year-old woman presenting with amnesia, apathy, work-related difficulties and mental stress. At presentation, her Mini-Mental State Examination score was 27 and her serum anticholinergic activity (SAA) was positive without medication or recent physical illnesses. In addition, magnetic resonance imaging revealed mild atrophy of the frontal and temporal lobes, with a relatively intact hippocampus. Consequently, we diagnosed mild cognitive impairment due to Alzheimer's disease and prescribed a cholinesterase inhibitor (donepezil, 10 mg/day); her SAA fully disappeared and clinical symptoms partially resolved. Addition of duloxetine coupled with environmental adjustments caused her cognitive function to return to a normal level, so we diagnosed pseudodementia due to depression. In this case, we believe that the simultaneous cholinergic burden and mental stress led to positive SAA, which made it reasonable to prescribe a cholinesterase inhibitor to ameliorate the associated acetylcholine hypoactivity. We believe that it is essential to recognize the importance of prescribing a cholinesterase inhibitor for specific patients, even those with pseudodementia, to control their clinical symptoms. Moreover, SAA might be a useful biomarker for identifying this subgroup of patients. We propose that anticholinergic activity appears endogenously in mood disorders (depression and bipolar disorder) and set out our rationalization for this hypothesis.

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.