Long-term progression of Alzheimer's disease in patients under antidementia drugs

A new accuracy metric under three classes when subclasses are involved and its confidence interval estimation

"Compound multi-class classification" refers to the setting where three or more main classes are involved and at least one of the main classes have multiple subclasses. A common practice in evaluating biomarker performance under "compound multi-class classification" is "subclasses pooling." In this article, we first explore the downsides of accuracy metrics based on pooled data. Then we propose a new accuracy measure proper for "compound multi-class classification" with three ordinal main classes, namely "volume under compoundR O C $$ ROC $$ surface (V U S C $$ VU{S}_C $$ )." The proposedV U S C $$ VU{S}_C $$ evaluates the accuracy of a biomarker appropriately by identifying main classes without requiring specification of an ordering for marker values of subclasses within each main class. For confidence interval estimation ofV U S C $$ VU{S}_C $$ , both parametric and nonparametric methods are studied, and simulation studies are carried out to assess coverage probabilities. A subset of Alzheimer's Disease Neuroimaging Initiative study dataset is analyzed.

An updated overview of recent and ongoing deep brain stimulation (DBS) trials in patients with dementia: a systematic review

BACKGROUND

Dementia affects more than 55 million people worldwide. Several technologies have been developed to slow cognitive decline: deep brain stimulation (DBS) of network targets in Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) have been recently investigated.

OBJECTIVE

This study aimed to review the characteristics of the populations, protocols, and outcomes of patients with dementia enrolled in clinical trials investigating the feasibility and efficacy of DBS.

MATERIALS AND METHODS

A systematic search of all registered RCTs was performed on Clinicaltrials.gov and EudraCT, while a systematic literature review was conducted on PubMed, Scopus, Cochrane, and APA PsycInfo to identify published trials.

RESULTS

The literature search yielded 2122 records, and the clinical trial search 15 records. Overall, 17 studies were included. Two of 17 studies were open-label studies reporting no NCT/EUCT code and were analysed separately. Of 12 studies investigating the role of DBS in AD, we included 5 published RCTs, 2 unregistered open-label (OL) studies, 3 recruiting studies, and 2 unpublished trials with no evidence of completion. The overall risk of bias was assessed as moderate-high. Our review showed significant heterogeneity in the recruited populations regarding age, disease severity, informed consent availability, inclusion, and exclusion criteria. Notably, the standard mean of overall severe adverse events was moderately high (SAEs: 9.10 ± 7.10%).

CONCLUSION

The population investigated is small and heterogeneous, published results from clinical trials are under-represented, severe adverse events not negligible, and cognitive outcomes uncertain. Overall, the validity of these studies requires confirmation based on forthcoming higher-quality clinical trials.

Baseline characterization of the ARMADA (Assessing Reliable Measurement in Alzheimer's Disease) study cohorts

INTRODUCTION

The National Institutes of Health (NIH) Toolbox (NIHTB) provides computerized measures of cognition, emotion, sensation, and motor abilities across the lifespan. The ARMADA (Assessing Reliable Measurement in Alzheimer's Disease and Cognitive Aging) study validated the NIHTB in individuals across the cognitive aging spectrum. This article reports the characteristics of our sample of participants.

METHODS

Participants were recruited across nine sites and classified clinically as cognitively normal (NC), with mild cognitive impairment (MCI), or with dementia of the Alzheimer's type (DAT.) They completed the NIHTB at multiple time points and many had at least one Alzheimer's biomarker previously obtained.

RESULTS

Groups differed with respect to dementia severity levels, as anticipated, but were well-matched across many demographic characteristics.

DISCUSSION

The ARMADA study demographics and baseline characteristics provide a suitable sample for validating the NIHTB across the cognitive aging spectrum. Other enriched samples (African American participants, Spanish NIHTB, 85+ years of age) will be reported elsewhere.

HIGHLIGHTS

There is a need for assessments that can detect the early stages of cognitive decline in older adults. The ARMADA (Assessing Reliable Measurement in Alzheimer's Disease and Cognitive Aging) study will validate the National Institutes of Health (NIH) Toolbox across the aging spectrum, including mild cognitive impairment (MCI) and dementia of the Alzheimer's type (DAT). Here we report the characteristics of participants. Groups were well-matched across most demographic characteristics, and clinical characteristics differed as expected. ARMADA study cohorts reflect their respective clinical syndromes for validating the NIH Toolbox.

Determinants of approved acetylcholinesterase inhibitor response outcomes in Alzheimer's disease: relevance for precision medicine in neurodegenerative diseases

Acetylcholinesterase inhibitors (ChEI) are the global standard of care for the symptomatic treatment of Alzheimer's disease (AD) and show significant positive effects in neurodegenerative diseases with cognitive and behavioral symptoms. Although experimental and large-scale clinical evidence indicates the potential long-term efficacy of ChEI, primary outcomes are generally heterogeneous across outpatient clinics and regional healthcare systems. Sub-optimal dosing or slow tapering, heterogeneous guidelines about the timing for therapy initiation (prodromal versus dementia stages), healthcare providers' ambivalence to treatment, lack of disease awareness, delayed medical consultation, prescription of ChEI in non-AD cognitive disorders, contribute to the negative outcomes. We present an evidence-based overview of determinants, spanning genetic, molecular, and large-scale networks, involved in the response to ChEI in patients with AD and other neurodegenerative diseases. A comprehensive understanding of cerebral and retinal cholinergic system dysfunctions along with ChEI response predictors in AD is crucial since disease-modifying therapies will frequently be prescribed in combination with ChEI. Therapeutic algorithms tailored to genetic, biological, clinical (endo)phenotypes, and disease stages will help leverage inter-drug synergy and attain optimal combined response outcomes, in line with the precision medicine model.

Apathy in UK Care Home Residents with Dementia: Longitudinal Course and Determinants

BACKGROUND

Apathy in dementia is common and associated with worse disease outcomes.

OBJECTIVE

To describe the longitudinal course of apathy in dementia and identify associated sociodemographic and disease-related factors.

METHODS

Prospective cohort study of UK care home residents with dementia. At baseline, 4, 8, 12, and 16 months, care home staff rated apathy using the Neuropsychiatric Inventory (clinically-significant apathy if≥4), dementia severity, and provided other sociodemographic information about each participant. We examined the prevalence and persistence of apathy and, in mixed linear models, its association with time, age, sex, dementia severity, antipsychotic use, and baseline apathy and other neuropsychiatric symptoms.

RESULTS

Of 1,419 included participants (mean age 85 years (SD 8.5)), 30% had mild dementia, 33% moderate, and 37% severe. The point prevalence of clinically-significant apathy was 21.4% (n = 304) and the 16-month period prevalence was 47.3% (n = 671). Of participants with follow-up data, 45 (3.8%) were always clinically-significantly apathetic, 3 (0.3%) were always sub-clinically apathetic, and 420 (36.2%) were never apathetic until death or end of follow-up. In adjusted models, apathy increased over time and was associated with having more severe dementia, worse baseline apathy and other neuropsychiatric symptoms.

CONCLUSION

It is important for clinicians to know that most people with dementia are not apathetic, though it is common. Most of those with significant symptoms of apathy improve without specific treatments, although some also relapse, meaning that intervention may not be needed. Future research should seek to target those people with persistent severe apathy and test treatments in this group.

Deep brain stimulation in Alzheimer's disease

Benefits from symptomatic and etiologic treatments in Alzheimer's Disease (AD), the most frequent dementia, are still insufficient. During the last decade, several studies showed that electrical stimulation of memory circuits could enhance memory in humans without memory impairment. First, improvement of verbal recollection was reported after deep brain stimulation (DBS) of the fornix in the hypothalamus in a patient treated for morbid obesity. Several studies in epileptic patients explored by deep electrodes reported that visuo-spatial memorization was facilitated by electrical stimulation of the entorhinal cortex or theta burst stimulation of the fornix. Recent studies suggested that DBS could be useful to modulate memory circuits in patients with cognitive decline. Phase I and II studies (about 50 patients) showed that chronic fornix DBS was safe and could achieved to stabilize or slow the memory decline of some patients with mild to moderate AD, especially older ones with less severe and/or advanced disease. DBS of the cholinergic nucleus of Meynert also has been explored in phase I studies in AD and Parkinson-related dementia. Growing experimental data suggest several mechanisms of action: restoration of hippocampal theta rhythms, enhanced long term potentiation, increase of hippocampal neurogenesis, neuroprotection by release of neurotrophic factors, diffuse reactivation of hypoactive neocortical associative regions. However, DBS in AD is still investigational and numerous issues remain to be solved before envisaging its use in clinical practice, including optimal anatomical DBS target, stimulation modalities (continuous, intermittent, theta-bursts, closed loop stimulation), best candidate patients, relevant targeted symptoms, ethical considerations.

Assessing the Progression of Alzheimer's Disease in Real-World Settings in Three European Countries

BACKGROUND

There exists considerable variation in disease progression rates among patients with Alzheimer's disease (AD).

OBJECTIVE

The primary objective of this observational study is to assess the progression of AD by characterizing cognitive, functional, and behavioral changes during the follow-up period between 6 and 24 months.

METHODS

A longitudinal prospective study with community-dwelling patients with an established clinical diagnosis of AD of mild to moderate severity was conducted in Germany, Spain and the UK. A sample of 616 patients from 69 sites was included.

RESULTS

Patients had a mean of 1.9 years (SD = 1.9) since AD diagnosis at study inclusion. Cognitive symptoms were reported to have first occurred a mean of 1.1 years (SD = 1.7) prior to AD diagnosis and 1.4 (SD = 1.8) years prior to AD treatment. Patients initially diagnosed with mild and moderate AD spent a median (95%CI) of 3.7 (2.8; 4.4) and 11.1 (6.1, 'not reached') years until progression to moderate and severe AD, respectively, according to the Mini-Mental State Examination (MMSE) scores. A mixed model developed for cognitive, functional, and neuropsychiatric scores, obtained from study patients at baseline and during follow-up period, showed progressive deterioration of AD patients over time.

CONCLUSION

The study showed a deterioration of cognitive, functional, and neuropsychiatric functions during the follow-up period. Cognitive deterioration was slightly faster in patients with moderate AD compared to mild AD. The duration of moderate AD can be overestimated due to the use of retrospective data, lack of availability of MMSE scores in clinical charts and exclusion of patients at time of institutionalization.

Modifiable, Non-Modifiable, and Clinical Factors Associated with Progression of Alzheimer's Disease

There is an extensive literature relating to factors associated with the development of Alzheimer's disease (AD), but less is known about factors which may contribute to its progression. This review examined the literature with regard to 15 factors which were suggested by PubMed search to be positively associated with the cognitive and/or neuropathological progression of AD. The factors were grouped as potentially modifiable (vascular risk factors, comorbidities, malnutrition, educational level, inflammation, and oxidative stress), non-modifiable (age at clinical onset, family history of dementia, gender, Apolipoprotein E ɛ4, genetic variants, and altered gene regulation), and clinical (baseline cognitive level, neuropsychiatric symptoms, and extrapyramidal signs). Although conflicting results were found for the majority of factors, a positive association was found in nearly all studies which investigated the relationship of six factors to AD progression: malnutrition, genetic variants, altered gene regulation, baseline cognitive level, neuropsychiatric symptoms, and extrapyramidal signs. Whether these or other factors which have been suggested to be associated with AD progression actually influence the rate of decline of AD patients is unclear. Therapeutic approaches which include addressing of modifiable factors associated with AD progression should be considered.

Functional Decline and Body Composition Change in Older Adults With Alzheimer Disease: A Retrospective Cohort Study at a Japanese Memory Clinic

BACKGROUND

There is a dearth of longitudinal data on body composition, function, and physical performance in persons with Alzheimer's disease (AD).

OBJECTIVES

The aim was to describe the trajectories of function, body composition, and physical performance in older adults with AD.

METHODS

In this retrospective cohort study, data were collected from older adults (n=1402) diagnosed with AD (mean age: 78.1 y old, women: 69.3%). Cognitive function was assessed using the mini-mental state examination. Proxy-reported instrumental and basic activities of daily living were assessed using the Lawton and Barthel indexes. Body composition was assessed using bioelectrical impedance analysis. Physical performance was assessed using the timed up and go test and grip strength.

RESULTS

Median (interquartile range) of follow-up time was 2.2 (1.2 to 3.6) years. Participants' mini-mental state examination score, Barthel index, and Lawton index declined over time. Skeletal muscle mass index and physical performance (timed up and go test and grip strength) decreased, while fat mass index increased with time. No significant changes or slight decline in weight and body mass index was observed.

CONCLUSIONS

Muscle mass and physical performance are likely to decline in older adults with AD. Clinicians should assess muscle mass and physical performance trajectories regularly in these patients and intervene appropriately.

Combination Drug Therapy for the Management of Alzheimer's Disease

Alzheimer's disease (AD) is the leading cause of dementia worldwide. Even though the number of AD patients is rapidly growing, there is no effective treatment for this neurodegenerative disorder. At present, implementation of effective treatment approaches for AD is vital to meet clinical needs. In AD research, priorities concern the development of disease-modifying therapeutic agents to be used in the early phases of AD and the optimization of the symptomatic treatments predominantly dedicated to the more advanced AD stages. Until now, available therapeutic agents for AD treatment only provide symptomatic treatment. Since AD pathogenesis is multifactorial, use of a multimodal therapeutic intervention addressing several molecular targets of AD-related pathological processes seems to be the most practical approach to modify the course of AD progression. It has been demonstrated through numerous studies, that the clinical efficacy of combination therapy (CT) is higher than that of monotherapy. In case of AD, CT is more effective, mostly when started early, at slowing the rate of cognitive impairment. In this review, we have covered the major studies regarding CT to combat AD pathogenesis. Moreover, we have also highlighted the safety, tolerability, and efficacy of CT in the treatment of AD.

Potentially modifiable factors associated with agitation and aggression in Alzheimer's disease: results of the ICTUS study

OBJECTIVES

To study potentially modifiable factors associated with the severity of agitation or aggression (A/A) symptoms among Alzheimer's disease (AD) patients.

DESIGN

Data from the Impact of Cholinergic Treatment Use (ICTUS) study, European longitudinal prospective observational study.

SETTING

Community dwelling outpatients included in 29 European memory clinics.

PARTICIPANTS

1375 participants with probable AD (Mini-Mental State Examination score of 10-26) with an informal caregiver.

MEASUREMENTS

At baseline and twice yearly over the two-year follow-up, patients underwent comprehensive clinical and neuropsychological assessments: sociodemographic data, cognitive status, functional impairment, and assessment of neuropsychiatric symptoms based on Neuro-Psychiatric Inventory (NPI). The ZARIT scale assessed the caregiver's burden. The variable of interest was the severity of the item of A/A of the NPI. To study factors associated to the severity of A/A symptoms six months later, a multivariate mixed regression model was used.

RESULTS

Frequency of A/A symptom varied from 30% to 34% at each visit. Two factors were found to be independently associated with the severity of A/A: (1) the presence of affective disorder (anxiety, depression, and/or irritability) that increased the severity of the A/A by 0.89 point (coefficient:0.89; 95% Confidence Interval (CI) = [0.48,1.30], p < 0.001), and (2) a severe caregiver burden that increased the severity of the A/A by 1.08 point (coefficient:1.08; 95% CI = [0.69,1.47], p < 0.001).

CONCLUSION

Research should evaluate whether the identification and treatment of an affective disorder along with the evaluation and optimal management of the caregiver would have a positive impact on the course of A/A in mild to moderate AD patients.

Cohort Effects in Progression Rate on Cognitive and Functional Measures in an Alzheimer's Disease Clinical Cohort

BACKGROUND

Accurate prediction of Alzheimer's disease (AD) cognitive and functional outcomes in clinical research requires consistent underlying rates of change over time.

OBJECTIVE

To examine cohort effects in AD progression rate over five years of follow-up using a clinical database of probable AD patients.

METHODS

Baseline characteristics of three cohorts enrolled from 1995-1999, 2000-2004, and 2005-2009 were compared using ANOVA and chi-square tests. Differences in 5-year decline on the Mini-Mental State Examination (MMSE), Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) and Clinical Dementia Rating Scale Sum of Boxes (CDR-SB), the Lawton and Brody Physical Self-maintenance Scale (PSMS), and Activities of Daily Living Scale (ADL) were assessed using longitudinal mixed effects regression, adjusting for age, sex, education, and other relevant clinical characteristics.

RESULTS

Cohorts 1 (n = 287), 2 (n = 257), and 3 (n = 374) did not differ on age, race, APOE genotype, or cognitive and functional measures. Educational attainment increased over time (13.4, 14.1, and 14.5 years, respectively, p < 0.001). Anti-dementia drug use at baseline was less common in Cohort 1 (32.2% versus 65.0%, and 66.8%, p < 0.001). The rate of decline in MMSE and CDR-SB did not differ across cohorts. ADAS-Cog scores for Cohort 2 declined more slowly than Cohort 3 (Btime ×cohort2 = -0.91 ± 0.35, p = 0.009), whereas Cohort 1 did not differ from cohort 3 (reference). Cohorts 1 and 2 differed from Cohort 3 in progression rate on the PSMS, but not the IADL.

CONCLUSIONS

There were no consistent temporal trends in progression rates over time. Longitudinal data over 15-20 years may be confidently pooled for outcomes analysis, but unexplained variability in rate of decline on some measures may occur.

The cholinergic system in the pathophysiology and treatment of Alzheimer's disease

Cholinergic synapses are ubiquitous in the human central nervous system. Their high density in the thalamus, striatum, limbic system, and neocortex suggest that cholinergic transmission is likely to be critically important for memory, learning, attention and other higher brain functions. Several lines of research suggest additional roles for cholinergic systems in overall brain homeostasis and plasticity. As such, the brain's cholinergic system occupies a central role in ongoing research related to normal cognition and age-related cognitive decline, including dementias such as Alzheimer's disease. The cholinergic hypothesis of Alzheimer's disease centres on the progressive loss of limbic and neocortical cholinergic innervation. Neurofibrillary degeneration in the basal forebrain is believed to be the primary cause for the dysfunction and death of forebrain cholinergic neurons, giving rise to a widespread presynaptic cholinergic denervation. Cholinesterase inhibitors increase the availability of acetylcholine at synapses in the brain and are one of the few drug therapies that have been proven clinically useful in the treatment of Alzheimer's disease dementia, thus validating the cholinergic system as an important therapeutic target in the disease. This review includes an overview of the role of the cholinergic system in cognition and an updated understanding of how cholinergic deficits in Alzheimer's disease interact with other aspects of disease pathophysiology, including plaques composed of amyloid-β proteins. This review also documents the benefits of cholinergic therapies at various stages of Alzheimer's disease and during long-term follow-up as visualized in novel imaging studies. The weight of the evidence supports the continued value of cholinergic drugs as a standard, cornerstone pharmacological approach in Alzheimer's disease, particularly as we look ahead to future combination therapies that address symptoms as well as disease progression.

Diagnosis and treatment of cognitive impairment

As a result of the aging population dementia is a growing challenge, especially in healthcare. Nevertheless, cognitive disorders are often not systematically evaluated, especially during hospital stays for other reasons; however, cognitive impairment is associated with a number of geriatric syndromes, including falls, delirium, dysphagia and lack of adherence to treatment plans. This article considers the current state of diagnosis and treatment of dementia. Non-pharmacological therapeutic approaches as well as current and future pharmacological treatment options are discussed. The drugs of choice for the symptomatic treatment of cognitive deficits in Alzheimer's disease and Parkinson-associated dementia are cholinesterase inhibitors and memantine; there is no specific pharmacological treatment for other types of dementia. Prevention and treatment of cardiovascular risk factors can potentially retard the progression of possibly all forms of dementia.

The Alzheimer's Disease Clinical Spectrum: Diagnosis and Management

Alzheimer's disease (AD) care requires timely diagnosis and multidisciplinary management. Evaluation involves structured patient and caregiver history and symptom-function reviews, examination, and testing (laboratory and neuroimaging) to delineate impairment level, determine the cognitive-behavioral syndrome, and diagnose cause. Clinical biomarkers are available to aid high confidence in etiologic diagnosis. Management uses psychoeducation, shared goal setting, and patient-caregiver dyad decision making. When combined, pharmacologic and nonpharmacologic therapies mitigate symptoms and reduce clinical progression and care burden. AD biopathologic processes develop over decades before symptoms manifest; this period is increasingly targeted in research as an opportunity to best delay or prevent AD dementia.

Opening the debate on deep brain stimulation for Alzheimer disease - a critical evaluation of rationale, shortcomings, and ethical justification

BACKGROUND

Deep brain stimulation (DBS) as investigational intervention for symptomatic relief from Alzheimer disease (AD) has generated big expectations. Our aim is to discuss the ethical justification of this research agenda by examining the underlying research rationale as well as potential methodological pitfalls. The shortcomings we address are of high ethical importance because only scientifically valid research has the potential to be ethical.

METHOD

We performed a systematic search on MEDLINE and EMBASE. We included 166 publications about DBS for AD into the analysis of research rationale, risks and ethical aspects. Fifty-eight patients were reported in peer-reviewed journals with very mixed results. A grey literature search revealed hints for 75 yet to be published, potentially enrolled patients.

RESULTS

The results of our systematic review indicate methodological shortcomings in the literature that are both scientific and ethical in nature. According to our analysis, research with human subjects was performed before decisive preclinical research was published examining the specific research question at stake. We also raise the concern that conclusions on the potential safety and efficacy have been reported in the literature that seem premature given the design of the feasibility studies from which they were drawn. In addition, some publications report that DBS for AD was performed without written informed consent from some patients, but from surrogates only. Furthermore, registered ongoing trials plan to enroll severely demented patients. We provide reasons that this would violate Art. 28 of the Declaration of Helsinki, because DBS for AD involves more than minimal risks and burdens, and because its efficacy and safety are not yet empirically established to be likely.

CONCLUSION

Based on our empirical analysis, we argue that clinical research on interventions of risk class III (Food and Drug Administration and European Medicines Agency) should not be exploratory but grounded on sound, preclinically tested, and disease-specific a posteriori hypotheses. This also applies to DBS for dementia as long as therapeutic benefits are uncertain, and especially when research subjects with cognitive deficits are involved, who may foreseeably progress to full incapacity to provide informed consent during the required follow-up period.

Disease-related determinants are associated with mortality in dementia due to Alzheimer's disease

Background

Survival after dementia diagnosis varies considerably. Previous studies were focused mainly on factors related to demographics and comorbidity rather than on Alzheimer’s disease (AD)-related determinants. We set out to answer the question whether markers with proven diagnostic value also have prognostic value. We aimed to identify disease-related determinants associated with mortality in patients with AD.

Methods

We included 616 patients (50% female; age 67 ± 8 years; mean Mini Mental State Examination score 22 ± 3) with dementia due to AD from the Amsterdam Dementia Cohort. Information on mortality was obtained from the Dutch Municipal Register. We used age- and sex-adjusted Cox proportional hazards analysis to study associations of baseline demographics, comorbidity, neuropsychology, magnetic resonance imaging (MRI) (medial temporal lobe, global cortical and parietal atrophy, and measures of small vessel disease), and cerebrospinal fluid (CSF) (β-amyloid 1–42, total tau, and tau phosphorylated at threonine 181 [p-tau]) with mortality (outcome). In addition, we built a multivariate model using forward selection.

Results

After an average of 4.9 ± 2.0 years, 213 (35%) patients had died. Age- and sex-adjusted Cox models showed that older age (HR 1.29 [95% CI 1.12–1.48]), male sex (HR 1.60 [95% CI 1.22–2.11]), worse scores on cognitive functioning (HR 1.14 [95% CI 1.01-1.30] to 1.31 [95% CI 1.13–1.52]), and more global and hippocampal atrophy on MRI (HR 1.18 [95% CI 1.01-1.37] and HR 1.18 [95% CI 1.02-1.37]) were associated with increased risk of mortality. There were no associations with comorbidity, level of activities of daily living, apolipoprotein E (APOE) ε4 status, or duration of disease. Using forward selection, the multivariate model included a panel of age, sex, cognitive tests, atrophy of the medial temporal lobe, and CSF p-tau.

Conclusions

In this relatively young sample of patients with AD, disease-related determinants were associated with an increased risk of mortality, whereas neither comorbidity nor APOE genotype had any prognostic value.

Electronic supplementary material

The online version of this article (10.1186/s13195-018-0348-0) contains supplementary material, which is available to authorized users.

Refining Mild-to-Moderate Alzheimer Disease Screening: A Tool for Clinicians

OBJECTIVES

Recent evidence suggests that a substantial minority of people clinically diagnosed with probable Alzheimer disease (AD) in fact do not fulfill the neuropathological criteria for the disease. A clinical hallmark of these phenocopies of AD is that these individuals tend to remain cognitively stable for extended periods of time, in contrast to their peers with confirmed AD who show a progressive decline. We aimed to examine the prevalence of patients clinically diagnosed with mild-to-moderate AD who do not experience the expected clinically significant cognitive decline and identify markers easily available in routine medical practice predictive of a stable cognitive prognosis in this population.

DESIGN

Data were obtained from two independent, longitudinal, observational multicenter studies in patients with mild-to-moderate AD.

SETTING

The two studies were the European "Impact of Cholinergic Treatment Use" (ICTUS) and the French "REseau sur la maladie d'Alzheimer FRançais" (REAL.FR).

PARTICIPANTS

We used prospective data of 756 patients enrolled in ICTUS and 340 enrolled in REAL.FR.

MEASUREMENTS

A prediction rule of cognitive decline was derived on ICTUS using classification and regression tree analysis and then cross-validated on REAL.FR. A range of demographic, clinical and cognitive variables were tested as predictor variables.

RESULTS

Overall, 27.9% of patients in ICTUS and 20.9% in REAL.FR did not decline over 2 years. We identified optimized cut-points on the verbal memory items of the Alzheimer Disease Assessment Scale-Cognitive Subscale capable of classifying patients at baseline into those who went on to decline and those who remained stable or improved over the duration of the trial.

CONCLUSION

The application of this simple rule would allow the identification of dementia cases where a more detailed differential diagnostic examination (eg, with biomarkers) is warranted. These findings are promising toward the refinement of AD screening in the clinic. For a further optimization of our classification rule, we encourage others to use our methodological approach on other episodic memory assessment tools designed to detect even small cognitive changes in patients with AD.

Describing the Sequence of Cognitive Decline in Alzheimer's Disease Patients: Results from an Observational Study

Background: Improved understanding of the pattern of cognitive decline in Alzheimer’s disease (AD) would be useful to assist primary care physicians in explaining AD progression to patients and caregivers.

Objective: To identify the sequence in which cognitive abilities decline in community-dwelling patients with AD.

Methods: Baseline data were analyzed from 1,495 patients diagnosed with probable AD and a Mini-Mental State Examination (MMSE) score ≤ 26 enrolled in the 18-month observational GERAS study. Proportional odds logistic regression models were applied to model MMSE subscores (orientation, registration, attention and concentration, recall, language, and drawing) and the corresponding subscores of the cognitive subscale of the Alzheimer’s Disease Assessment Scale (ADAS-cog), using MMSE total score as the index of disease progression. Probabilities of impairment start and full impairment were estimated at each MMSE total score level.

Results: From the estimated probabilities for each MMSE subscore as a function of the MMSE total score, the first aspect of cognition to start being impaired was recall, followed by orientation in time, attention and concentration, orientation in place, language, drawing, and registration. For full impairment in subscores, the sequence was recall, drawing, attention and concentration, orientation in time, orientation in place, registration, and language. The sequence of cognitive decline for the corresponding ADAS-cog subscores was remarkably consistent with this pattern.

Conclusion: The sequence of cognitive decline in AD can be visualized in an animation using probability estimates for key aspects of cognition. This might be useful for clinicians to set expectations on disease progression for patients and caregivers.

Longitudinal course of behavioural and psychological symptoms of dementia: systematic review

BACKGROUND

More information about the pattern of behavioural and psychological symptoms of dementia (BPSD) in the course of dementia is needed to inform patients and clinicians and to design future interventions.

AIMS

To determine the persistence and incidence of BPSD and their relation to cognitive function, in individuals with dementia or in cohorts investigated for dementia onset.

METHOD

A systematic literature review analysed the baseline prevalence, persistence and incidence of 11 symptoms. The review was conducted according to established guidelines with the exception that we could not exclude the possibilities of bias in the studies examined.

RESULTS

The 59 included studies showed considerable heterogeneity in their objectives and methods. The symptoms hyperactivity and apathy showed high persistence and incidence; depression and anxiety low or moderate persistence and moderate incidence; and psychotic symptoms low persistence with moderate or low incidence.

CONCLUSIONS

Despite heterogeneity across studies in terms of setting, focus and length of follow-up, there were clinically relevant differences in the longitudinal courses of different BPSD. Apathy was the only symptom with high baseline prevalence, persistence and incidence during the course of dementia.

Predictive factors for disease progression in patients with early-onset Alzheimer's disease

BACKGROUND

Only a few studies have investigated disease progression in patients with early-onset Alzheimer's disease (EOAD). Therefore, the aim of this study was to investigate disease progression in patients with EOAD and the influence of various factors, such as gender, education, and apolipoprotein E (APOE) genotype on disease progression.

METHODS

A total of 288 EOAD patients were enrolled in the study. Linear mixed models were used to investigate the rate of cognitive and functional decline in terms of age at onset, gender, education, follow-up period, and APOE genotype.

RESULTS

EOAD patients showed an annual decline of -1.54 points/years in the Korean version mini-mental examination score, an annual increase of 3.46 points/year in the Seoul instrumental activities of daily living (SIADL) score, and an annual increase of 1.15 points/year in the clinical dementia rating scale-sum of boxes score. After stratification, higher educated patients showed faster disease progression in all three parameters, and female patients demonstrated faster disease progression as assessed by the SIADL score. Age at onset and APOE genotype had no influence on disease progression.

CONCLUSION

We confirmed the rate of disease progression in Korean patients with EOAD in real-life hospital-based clinical practice. The results of this study suggest that education and female gender, not APOE genotype, may be important as independent strong predictive factors for disease progression in patients with EOAD.

Clinical Recommendations for the Use of Donepezil 23 mg in Moderate-to-Severe Alzheimer's Disease in the Asia-Pacific Region

Background

The ‘Asia-Pacific Expert Panel (APEX) for donepezil 23 mg’ met in November 2015 to review evidence for the recently approved high dose of donepezil and to provide recommendations to help physicians in Asia make informed clinical decisions about using donepezil 23 mg in patients with moderate-to-severe Alzheimer's disease (AD).

Summary

In a global phase III study (study 326) in patients with moderate-to-severe AD, donepezil 23 mg/day demonstrated significantly greater cognitive benefits versus donepezil 10 mg/day, with a between-treatment difference in mean change in the Severe Impairment Battery score of 2.2 points (p < 0.001) in the overall population and 3.1 points (p < 0.001) in patients with advanced AD. A subanalysis of study 326 demonstrated that the benefits and risks associated with donepezil 23 mg/day versus donepezil 10 mg/day in Asian patients with moderate-to-severe AD were comparable to those in the global study population.

Key Message

Donepezil 23 mg is a valuable treatment for patients with AD, particularly those with advanced disease. The APEX emphasized the importance of patient selection (AD severity, tolerability of lower doses of donepezil, and absence of contraindications), a stepwise titration strategy for dose escalation, and appropriate monitoring and counseling of patients and caregivers in the management of patients with AD.

High tau levels in cerebrospinal fluid predict nursing home placement and rapid progression in Alzheimer's disease

Background

Increased concentrations of cerebrospinal fluid (CSF) total tau (t-tau) and phosphorylated tau, as well as decreased amyloid-β 42 peptide, are biomarkers of Alzheimer’s disease (AD) pathology, but few studies have shown an association with AD progression rate. We hypothesized that high CSF tau, as a marker of ongoing neurodegeneration, would predict a more aggressive course of AD, using time to nursing home placement (NHP) as the main outcome.

Methods

Our sample inlcuded 234 patients with mild cognitive impairment (MCI) due to AD (n = 134) or mild to moderate AD (n = 100) who underwent lumbar puncture at a memory clinic and were followed for 2–11 years (median 4.9 years).

Results

Individuals with CSF t-tau in the highest quartile (≥900 ng/L) had a higher ratio of NHP, both in the total cohort and in patients with MCI only (adjusted HR 2.17 [95 % CI 1.24–3.80]; HR 2.37 [95 % CI 1.10–5.09], respectively), than the lowest quartile. The association between high t-tau levels and future steep deterioration was confirmed in analyses with conversion to moderate dementia (HR 1.66; 95 % CI 1.08–2.56), rapid decline in Mini Mental State Examination score (≥4-point drop/12 months), and dying in severe dementia as outcomes.

Conclusions

To our knowledge, this is the first study to show that high CSF t-tau levels predict early NHP and conversion to moderate dementia in an AD cohort. Selecting patients with high CSF t-tau, indicating more aggressive neurodegeneration and steeper decline, for AD immunotherapy trials might increase the possibility of showing contrast between active treatment and placebo.

Electronic supplementary material

The online version of this article (doi:10.1186/s13195-016-0191-0) contains supplementary material, which is available to authorized users.

Longitudinal Associations between Survival in Alzheimer's Disease and Cholinesterase Inhibitor Use, Progression, and Community-Based Services

BACKGROUND/AIMS

Factors including rate of disease progression, different aspects of cholinesterase inhibitor (ChEI) treatment, and use of community-based services might affect the longitudinal outcome of Alzheimer's disease (AD). Whether these factors alter life expectancy in AD is unclear. We therefore examined the association between long-term ChEI therapy and survival.

METHODS

The present study included 1,021 patients with a clinical diagnosis of AD and a Mini-Mental State Examination score of 10-26 at baseline from a 3-year, prospective, multicenter study of ChEI therapy in clinical practice. The relationship of potential predictors with mortality was analyzed using Cox regression models.

RESULTS

After up to 16 years of follow-up, 841 (82%) of the participants had died. In the Alzheimer's Disease Assessment Scale-cognitive subscale, a mean decline of ≥ 4 points/year or ≥ 2 points/year on the Physical Self-Maintenance Scale was a risk factor for an earlier death. In the multivariate models, longer survival was associated with higher ChEI dose and longer duration of treatment. Users of community-based services at baseline exhibited a 1-year shorter mean life expectancy than nonusers.

CONCLUSION

A longer survival time can be anticipated for AD patients with slower deterioration who receive and tolerate higher ChEI doses and a longer duration of treatment.

Beneficial Effects of an Integrated Psychostimulation Program in Patients with Alzheimer's Disease

BACKGROUND

The existing pharmacological treatments for Alzheimer's disease (AD) can only slow the progression of symptoms or delay admission to long-term care facilities. The beneficial effects of non-drug treatments are poorly studied.

OBJECTIVE

To describe the effects of an Integrated Psychostimulation Program (IPP) in patients with mild-moderate AD treated with acetylcholinesterase inhibitors; and to identify factors related to greater benefit of the IPP.

METHODS

206 patients (mean age = 75.9 years; MMSE = 19.6) were evaluated before starting the IPP and 3, 6, 9, and 12 months later. Measures included: Mini-Mental State Examination (MMSE), Cognitive Subscale of Alzheimer's Disease Assessment Scale (ADAS-Cog), Rapid Disability Rating Scale (RDRS-2), and Neuropsychiatric Inventory Questionnaire (NPI-Q).

RESULTS

Patients remained cognitively stable (MMSE/ADAS-Cog) for more than 6 months and significantly worsened at 9-month and 12-month follow-ups, without clinically significant functional changes (RDRS-2) or psychiatric symptoms(NPI-Q). The mean annual change on MMSE and ADAS-Cog were 2.06 and 3.56 points, respectively, lower than the annual decline demonstrated previously in similar patients (2.4 and 4.5, respectively). 42.7% of patients maintained or improved global cognitive scores between baseline and 12-month follow-up. The patients who maintained cognitive functions were older than those who did not (77.5 versus 74.7 years).

CONCLUSIONS

The IPP may be an effective treatment to maintain cognition, functionality, and psychiatric symptoms in AD patients pharmacologically treated, and older age seems to increase beneficial effects of IPP.

Slowing the progression of Alzheimer's disease; what works?

Alzheimer's disease (AD) is an age-related progressive dementia, which is increasing in prevalence world-wide. Typically affecting short-term memory at onset, this devastating illness advances to impair all aspects of cognition, as well as non-cognitive domains. Although much effort has been made in recent years to develop disease-modifying treatments, medications which provided promising results in pre-clinical research have so far faltered in human clinical trials. Attention has recently shifted into trying to identify preventative measures that may delay the onset of the illness. Preventative factors include physical activity, proper diet, cognitive stimulation and the management of conditions such as hypertension, diabetes and obesity. However, it remains imperative to identify approaches that may help patients already diagnosed with the illness. Alongside pharmacological research, much work has been done on uncovering strategies which may slow down the progression of AD. This review aims to summarize evidence supporting or refuting methods impacting on the progression of the disease. AD remains a chronic and serious condition, therefore any intervention delaying the onset of moderate/severe symptoms will have a significant impact on patients and their families.

Risk Factors for Progression of Alzheimer Disease in a Canadian Population: The Canadian Outcomes Study in Dementia (COSID)

OBJECTIVE

To determine risk factors for clinically significant progression during 12 months in patients with mild-to-moderate Alzheimer disease.

METHOD

Community-dwelling patients with mild-to-moderate Alzheimer disease were enrolled in a 3-year prospective study, the Canadian Outcomes Study in Dementia (commonly referred to as COSID), at 32 Canadian sites. Assessments included the Global Deterioration Scale (GDS) for disease severity, the Mini-Mental State Examination (MMSE) for cognition, the Functional Autonomy Measurement System (SMAF) for daily functioning, and the NeuroPsychiatric Inventory (NPI) for behaviour, measured at baseline and at 12 months. Logistic regression identified factors associated with GDS decline, and subsequent stepwise regression identified key independent predictors. Area under the curve (AUC) was then calculated for the model.

RESULTS

Among 488 patients (mean age 76.5 years [SD 6.4], MMSE 22.1 [SD4.6], 44.1% male), 225 (46%) showed GDS decline. After adjusting for age, baseline risk factors for deterioration included the following: poorer cognition (lower MMSE score, OR 0.55; 95% CI 0.4 to 0.72 per 5 points, P ≤ 0.001), greater dependence (lower SMAF, OR 0.72; 95% CI 0.63 to 0.83 per 5 points, P ≤ 0.001), and more neuropsychiatric symptoms (higher NPI, OR 1.11; 95% CI 1.02 to 1.2 per 5 points, P = 0.02), with a protective effect of male sex (OR 0.59; 95% CI 0.39 to 0.9, P = 0.02), and higher (worse) GDS score (very mild, compared with mild OR 0.25; 95% CI 0.09 to 0.70, P ≤ 0.01; compared with moderate, OR 0.08; 95% CI 0.03 to 0.23, P < 0.001; compared with moderately severe, OR 0.03; 95% CI 0.01 to 0.11, P < 0.001). The AUC was 73% (P < 0.001) (sensitivity 90% and specificity 33%).

CONCLUSION

The progression of Alzheimer disease in Canada can be predicted using readily available clinical information.

Deep brain stimulation of the nucleus basalis of Meynert in Alzheimer's dementia

Cholinergic neurons of the medial forebrain are considered important contributors to brain plasticity and neuromodulation. A reduction of cholinergic innervation can lead to pathophysiological changes of neurotransmission and is observed in Alzheimer's disease. Here we report on six patients with mild to moderate Alzheimer's disease (AD) treated with bilateral low-frequency deep brain stimulation (DBS) of the nucleus basalis of Meynert (NBM). During a four-week double-blind sham-controlled phase and a subsequent 11-month follow-up open label period, clinical outcome was assessed by neuropsychological examination using the Alzheimer's Disease Assessment Scale-cognitive subscale as the primary outcome measure. Electroencephalography and [(18)F]-fluoro-desoxyglucose positron emission tomography were, besides others, secondary endpoints. On the basis of stable or improved primary outcome parameters twelve months after surgery, four of the six patients were considered responders. No severe or non-transitional side effects related to the stimulation were observed. Taking into account all limitations of a pilot study, we conclude that DBS of the NBM is both technically feasible and well tolerated.

The Progression of Alzheimer's Disease Can Be Assessed with a Short Version of the CERAD Neuropsychological Battery: The Kuopio ALSOVA Study

Background/Aims

Measuring and predicting Alzheimer's disease (AD) progression is important in order to adjust treatment and allocate care resources. We aimed to identify a combination of subtests from the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Battery (CERAD-NB) that best correlated with AD progression in follow-up as well as to predict AD progression.

Method

A total of 236 participants with very mild [Clinical Dementia Rating (CDR) = 0.5] or mild AD (CDR = 1.0) at baseline were followed up for 3 years. The CERAD-NB and Mini-Mental State Examination (MMSE) were used to assess cognition, and the CDR scale sum of boxes (CDR-sb) was employed to evaluate AD progression. Generalized estimating equations were used to develop models to predict and follow up disease progression.

Results

Performance declined on all CERAD-NB subtests. The ability of the separate subtests to distinguish between groups (baseline CDR = 0.5 or 1.0) diminished during follow-up. The best combination of subtests that explained 62% of CDR-sb variance in follow-up included verbal fluency, constructional praxis, the clock drawing test, and the MMSE. Baseline values of the same combination predicted 37% of the CDR-sb change.

Conclusion

A short version of the CERAD-NB subtests provides a promising and time-efficient alternative for measuring cognitive deterioration during AD follow-up. Although the initial signs of AD include memory difficulties, it may be useful to assess non-memory tasks in follow-up.

Hierarchical structure of the activities of daily living scale in dementia

OBJECTIVES

To describe the sequence of basic activities of daily living (ADL) loss to determine whether there is a hierarchical structure of ADL in dementia in two epidemiological prospective studies: the Paquid study and the Three City Study (3C).

DESIGN

Two prospective population-based cohort studies: Paquid (over 22 years of follow-up) and 3C (over 10 years of follow-up).

SETTING

Paquid Study, Gironde, Dordogne, France; The Three Cities Study, Bordeaux, Montpellier, Dijon, France.

MAIN OUTCOMES MEASURES

We analyzed four ADL of the Katz scale: bathing, dressing, transferring and feeding. The a priori hierarchical relationship of the 4 activities tested was 1) no ADL-disability at all four activities; 2) moderate ADL-disability, or disability at bathing and/or dressing (and no disability in transferring nor feeding); and 3) severe ADL-disability, or disability in bathing and/or dressing and transferring and/or feeding. We performed a Guttman scale analysis to establish the hierarchical properties scale.

RESULTS

In total, 845 incident cases of dementia were included, among which 838 cases (99.2%) were without any missing data for ADL. Upon diagnosis of dementia, 564 subjects (67.3%) had no ADL-disability, 236 (26.2%) had moderate ADL-disability, and 38 subjects (4.5%) had severe disability. The a priori hierarchy was respected with non-discordance.

CONCLUSION

We defined 3 simple relevant stages of ADL functional decline in dementia that would be easy to collect in clinical practice: stage 1, subjects with no major ADL disabilities; stage 2, subjects with complete disability in bathing and/or dressing; and stage 3, subjects with complete disability in all 4 tasks.

Maximizing ADL performance to facilitate aging in place for people with dementia

The purpose of this article is to review the effect of dementia on activities of daily living and consequently on the ability to age in place. Types of evaluation and information conferred from different types of assessment are discussed. Evidence-based interventions for preventing and minimizing activities-of-daily-living disability are outlined.

Differences in drug therapy between dementia disorders in the Swedish dementia registry: a nationwide study of over 7,000 patients

BACKGROUND/AIMS

We aimed to study whether there are differences between dementia disorders and the use of anti-dementia drugs and antipsychotics (neuroleptics) in a large population of dementia patients.

METHODS

Information about dementia disorders was obtained from the national Swedish Dementia Registry (SveDem) 2007-2010 (n = 7,570). Multivariate logistic regression analysis was performed to investigate the association between dementia disorders and the use of anti-dementia drugs and antipsychotics, after adjustment for age, sex, residential setting, living alone, MMSE score and number of other drugs (a proxy for overall co-morbidity).

RESULTS

More than 80% of the Alzheimer's disease (AD) and 86% of dementia with Lewy bodies (DLB) patients used anti-dementia drugs. Women were more likely than men to be treated with cholinesterase inhibitors. A higher MMSE score was positively associated with the use of cholinesterase inhibitors, but negatively associated with NMDA receptor antagonists and antipsychotics. Use of antipsychotics was 6% overall; however, it was 16% in DLB patients with an adjusted odds ratio of 4.2 compared to AD patients.

CONCLUSION

Use of anti-dementia drugs in AD was in agreement with Swedish guidelines. However, use of antipsychotics in DLB patients was high, which might be worrying given the susceptibility of DLB patients to antipsychotics.

Retrospective cohort study of the efficacy of caprylic triglyceride in patients with mild-to-moderate alzheimer's disease

BACKGROUND

The purpose of this study was to evaluate the effects of caprylic triglyceride (CT) in patients with mild-to-moderate Alzheimer's disease (AD) in routine clinical practice via review of medical records and caregiver questionnaires.

METHODS

Participants were outpatients aged ≥50 years with a diagnosis of probable mild-to-moderate AD who had received CT for ≥6 months. The primary outcome was change from baseline in the patient's condition as rated by the treating physician using a physician's overall assessment.

RESULTS

A total of 55 patients were included. The physician's overall assessment indicated that ~80% of patients who had CT added to ongoing pharmacotherapy were stable or improved. Mini-Mental State Examination scores also remained stable over 15 months of therapy (20.6 ± 3.0 at baseline and 20.1 ± 5.6 at follow-up, P = 0.5233, n = 27). Caregiver assessments indicated that most patients were stable or improved with respect to memory and ability to carry out activities of daily living. The most frequent adverse events with CT involved the gastrointestinal system.

CONCLUSION

Results from this chart review indicate that addition of CT to pharmacotherapy was associated with stable disease or improvement over a follow-up period of 18.8 months.

Retrospective case studies of the efficacy of caprylic triglyceride in mild-to-moderate Alzheimer's disease

Under normal conditions, the adult human brain is fueled primarily by glucose. A prominent feature of Alzheimer's disease (AD) is region-specific decreases in cerebral glucose metabolism. Ketone bodies are a group of compounds produced from fat stores during periods of low glucose availability that can provide an alternative to glucose for brain metabolism. Consumption of sufficient quantities of caprylic triglyceride (CT) increases plasma concentrations of ketone bodies and may be beneficial in conditions of compromised glucose metabolism, such as AD. The present study describes the use of CT in mild-to-moderate AD in routine clinical practice. Case records from eight patients with extensive monitoring of cognitive function using the Mini-Mental State Examination (MMSE) and who had received CT for ≥6 months were reviewed. All were outpatients aged ≥50 years, cared for in standard practice, had a diagnosis of probable AD of mild-to-moderate severity (MMSE 14-24), and had received CT for at least 6 months in addition to other approved pharmacotherapy for AD. Response to CT administration as measured by MMSE scores varied by patient. However, the rate of decline in MMSE scores appeared slower than previously published reports for patients treated with pharmacotherapy alone. Profiling of individual patients may provide insight regarding those most likely to benefit from addition of CT to currently approved AD pharmacotherapy.

Cognitive change in donepezil treated patients with vascular or mixed dementia

BACKGROUND

vascular dementia (VaD) and mixed Alzheimer's disease (AD/VaD) are common. How best to monitor treatment is not clear. Our objective was to compare responsiveness and construct validity of change scores, following donepezil treatment, of the standardized Mini-Mental State Examination (sMMSE) and other measures potentially usable in primary care.

METHODS

A six-month, outcome measurement study. The Disability Assessment for Dementia (DAD), CLOX-1 and 2, Phonetic Fluency, a short Neuropsychiatric Inventory, (the NPI-Q), Clinical Global Impression (CGI) and the SymptomGuide™ (SG) were measured. Construct validity was tested by correlating change scores, and responsiveness by calculating standardized response means (SRMs).

RESULTS

Of 148 treated patients, 116 completed. The mean sMMSE increased by 0.7 (95% Confidence Interval (CI) = -0.005, 1.41; p=0.06; SRM= 0.15). There was no statistically significant difference in the DAD. The NPI-Q (-1.4; 95% CI = -2.08, -0.72; p<0.01; SRM=0.24), CLOX-1 (0.9; 95% CI = 0.19, 1.61; p<0.01; SRM=0.21), CLOX-2 (0.9; 95% CI = 0.17, 1.63; p=0.03; SRM=0.26), Phonetic Fluency (0.9; 95% CI = 0.19, 1.61; p=0.02; SRM=0.21) and SG (0.35; 95% CI = 0.20,0.51; p<0.01; SRM=0.28) each detected significant improvement. The CGI suggested improvement in 74 completers (64%) - mostly "minimal" (44/116, 38%) - while 21/116 (18%) were worse. Change scores at 24 weeks were at best modestly correlated with each other (range -0.22 to 0.30).

DISCUSSION

Different measures showed different responsiveness, in a setting in which the mean treatment effect seems to have been small, but clinically detectable. Patient-centered and executive function measures might be useful in vascular and mixed dementia.

Memantine and cholinesterase inhibitors: complementary mechanisms in the treatment of Alzheimer's disease

This review describes the preclinical mechanisms that may underlie the increased therapeutic benefit of combination therapy-with the N-methyl-D-aspartate receptor antagonist, memantine, and an acetylcholinesterase inhibitor (AChEI)-for the treatment of Alzheimer's disease (AD). Memantine, and the AChEIs target two different aspects of AD pathology. Both drug types have shown significant efficacy as monotherapies for the treatment of AD. Furthermore, clinical observations indicate that their complementary mechanisms offer superior benefit as combination therapy. Based on the available literature, the authors have considered the preclinical mechanisms that could underlie such a combined approach. Memantine addresses dysfunction in glutamatergic transmission, while the AChEIs serve to increase pathologically lowered levels of the neurotransmitter acetylcholine. In addition, preclinical studies have shown that memantine has neuroprotective effects, acting to prevent glutamatergic over-stimulation and the resulting neurotoxicity. Interrelations between the glutamatergic and cholinergic pathways in regions of the brain that control learning and memory mean that combination treatment has the potential for a complex influence on disease pathology. Moreover, studies in animal models have shown that the combined use of memantine and the AChEIs can produce greater improvements in measures of memory than either treatment alone. As an effective approach in the clinical setting, combination therapy with memantine and an AChEI has been a welcome advance for the treatment of patients with AD. Preclinical data have shown how these drugs act via two different, but interconnected, pathological pathways, and that their complementary activity may produce greater effects than either drug individually.

Memantine in patients with Alzheimer's disease receiving donepezil: new analyses of efficacy and safety for combination therapy

Introduction

Memantine and cholinesterase inhibitors potentially offer additional benefits in Alzheimer's disease (AD) when used together. This study assessed the efficacy and safety of combination treatment with memantine added to stable donepezil in patients with moderate to severe AD, and in a subset with moderate AD.

Methods

Post hoc meta-analyses of data combined from two 24-week, randomised, double-blind, placebo-controlled trials of memantine 20 mg/day versus placebo, added to a stable cholinesterase inhibitor, were conducted. Data were included for all patients receiving donepezil 10 mg/day with Mini-Mental State Examination (MMSE) scores < 20 (n = 510). Efficacy was assessed using measures of cognition, function, and global status. Furthermore, marked clinical worsening, defined as concurrent deterioration from baseline in the three main efficacy domains, and safety, measured by treatment-emergent adverse events, were assessed. Analyses were performed for patients with moderate to severe AD (MMSE 5-19; MOD-SEV subgroup), and also for patients with moderate AD (MMSE 10-19; MOD subgroup; n = 367).

Results

At week 24, in the MOD-SEV subgroup, patients receiving memantine added to donepezil significantly outperformed those receiving placebo added to donepezil in measures of cognition (P < 0.0001), function (P = 0.02), and global status (P = 0.010), with standardised mean differences (SMDs) of 0.36, 0.21, and 0.23, respectively (all last observation carried forward). Similarly, in the MOD subgroup, significant benefits were observed for cognition (P = 0.008), function (P = 0.04) and global status (P = 0.008), with SMDs of 0.28, 0.21, and 0.28, respectively. Significantly fewer patients receiving memantine added to donepezil showed marked clinical worsening than those receiving placebo added to donepezil, in both subgroups (MOD-SEV: 8.7% versus 20.4%, P = 0.0002; MOD: 5.9% versus 15.0%, P = 0.006). The incidence of adverse events was similar between treatment groups.

Conclusions

These results support and extend previous evidence that combination treatment with memantine added to stable donepezil in patients with moderate AD, and in those with moderate to severe AD, is associated with significant benefits in reducing 24-week decline in cognition, function and global status. Combination treatment produces substantially reduced rates of marked clinical worsening, has good safety and tolerability, and generates effect sizes that are both statistically significant and clinically meaningful.