Biomarker-based prognosis for people with mild cognitive impairment (ABIDE): a modelling study

BACKGROUND

Biomarker-based risk predictions of dementia in people with mild cognitive impairment are highly relevant for care planning and to select patients for treatment when disease-modifying drugs become available. We aimed to establish robust prediction models of disease progression in people at risk of dementia.

METHODS

In this modelling study, we included people with mild cognitive impairment (MCI) from single-centre and multicentre cohorts in Europe and North America: the European Medical Information Framework for Alzheimer's Disease (EMIF-AD; n=883), Alzheimer's Disease Neuroimaging Initiative (ADNI; n=829), Amsterdam Dementia Cohort (ADC; n=666), and the Swedish BioFINDER study (n=233). Inclusion criteria were a baseline diagnosis of MCI, at least 6 months of follow-up, and availability of a baseline Mini-Mental State Examination (MMSE) and MRI or CSF biomarker assessment. The primary endpoint was clinical progression to any type of dementia. We evaluated performance of previously developed risk prediction models-a demographics model, a hippocampal volume model, and a CSF biomarkers model-by evaluating them across cohorts, incorporating different biomarker measurement methods, and determining prognostic performance with Harrell's C statistic. We then updated the models by re-estimating parameters with and without centre-specific effects and evaluated model calibration by comparing observed and expected survival. Finally, we constructed a model combining markers for amyloid deposition, tauopathy, and neurodegeneration (ATN), in accordance with the National Institute on Aging and Alzheimer's Association research framework.

FINDINGS

We included all 2611 individuals with MCI in the four cohorts, 1007 (39%) of whom progressed to dementia. The validated demographics model (Harrell's C 0·62, 95% CI 0·59-0·65), validated hippocampal volume model (0·67, 0·62-0·72), and updated CSF biomarkers model (0·72, 0·68-0·74) had adequate prognostic performance across cohorts and were well calibrated. The newly constructed ATN model had the highest performance (0·74, 0·71-0·76).

INTERPRETATION

We generated risk models that are robust across cohorts, which adds to their potential clinical applicability. The models could aid clinicians in the interpretation of CSF biomarker and hippocampal volume results in individuals with MCI, and help research and clinical settings to prepare for a future of precision medicine in Alzheimer's disease. Future research should focus on the clinical utility of the models, particularly if their use affects participants' understanding, emotional wellbeing, and behaviour.

FUNDING

ZonMW-Memorabel.

Longitudinal cerebrospinal fluid biomarker trajectories along the Alzheimer's disease continuum in the BIOMARKAPD study

INTRODUCTION

Within-person trajectories of cerebrospinal fluid (CSF) biomarkers in Alzheimer's disease (AD) are not well defined.

METHODS

We included 467 subjects from the BIOMARKAPD study with at least two serial CSF samples. Diagnoses were subjective cognitive decline (n = 75), mild cognitive impairment (n = 128), and AD dementia (n = 110), and a group of cognitively unimpaired subjects (n = 154) were also included. We measured baseline and follow-up CSF levels of total tau (t-tau), phosphorylated tau (p-tau), YKL-40, and neurofilament light (NfL). Median CSF sampling interval was 2.1 years.

RESULTS

CSF levels of t-tau, p-tau, NfL, and YKL-40 were 2% higher per each year of baseline age in controls (P <.001). In AD, t-tau levels were 1% lower (P <.001) and p-tau levels did not change per each year of baseline age. Longitudinally, only NfL (P <.001) and YKL-40 (P <.02) increased during the study period.

DISCUSSION

All four CSF biomarkers increase with age, but this effect deviates in AD for t-tau and p-tau.

Assessing physician attitudes and perceptions of Alzheimer's disease across Europe

Given the important role that physicians play in clinical care, disease advocacy, national health policy making and clinical research, the IMPACT survey sought to assess the attitudes and perceptions of physicians in 3 general categories: diagnosis and treatment of Alzheimer's disease (AD); caregivers and families of patients with AD; and the role of government in dealing with this disease and its consequences. Survey respondents comprised a total of 250 generalists and 250 specialists (neurologists, geriatricians, neuro-psychiatrists, psychiatrists and psychogeriatricians) from France, Germany, Italy, Spain and the United Kingdom. Physicians were aged 25 to 69 years, in practice for between 5 and 30 years and currently spending more than 50% of their time in direct patient care. Results showed that a sizable majority of physicians throughout Europe, specialists and generalists alike, agree that: 1) AD is underdiagnosed and undertreated; 2) patients and families are not prepared to recognise the early symptoms of the disease; 3) early treatment can help to slow the progression of the disease; and 4) more effective treatments are needed. Attitudes were statistically significantly different between some groups of physicians regarding disclosure of the diagnosis of AD, the benefits of lifestyle modification, and the value of AD-specific medication in patients whose symptoms are worsening. Differences in attitudes and perceptions of AD between specialists and generalists were limited; differences between countries were more common and of greater magnitude, particularly with respect to barriers to the use of prescription medications.

Consensus statement on dementia education and training in Europe

OBJECTIVES

The aim of the current statement is to agree on: (1) what is the current situation with education and training on dementia in Europe; (2) what are the minimum educational requirements for professionals (neurologists, psychiatrists, primary care providers, nurses, biologists, neuroradiologists, etc.) regarding Alzheimer's disease and dementia, and (3) how to start a course of action for the future.

DESIGN

In 2005, a simple questionnaire was sent to members of the European Alzheimer's Disease Consortium (EADC) concerning the education and training on dementia in their countries. Fourteen universities of the respective countries responded to this simple questionnaire. The answers varied, and the conclusion of this effort was that little was done concerning the training of students and health professionals on dementia. In 2008, another more structured and specified questionnaire was sent to professors in different universities of the same countries.

RESULTS

The answers obtained were different from those of the previous questionnaire and demonstrated that it is very difficult to know about training and education in the field of dementia in every European country.

CONCLUSION

From the data collected, it seems that although in the recent past little had been done concerning training on dementia, nowadays training has been developed in most European countries, and relevant educational projects exist both for medical students and doctors during their specialty training. Our main purpose is to develop training material or develop specific courses to improve the professional knowledge about dementia so that best medical and non-medical practice is implemented.

Early and differential diagnosis of dementia and mild cognitive impairment: design and cohort baseline characteristics of the German Dementia Competence Network

BACKGROUND

The German Dementia Competence Network (DCN) has established procedures for standardized multicenter acquisition of clinical, biological and imaging data, for centralized data management, and for the evaluation of new treatments.

METHODS

A longitudinal cohort study was set up for patients with mild cognitive impairment (MCI), patients with mild dementia and control subjects. The aims were to establish the diagnostic, differential diagnostic and prognostic power of a range of clinical, laboratory and imaging methods. Furthermore, 2 clinical trials were conducted with patients suffering from MCI and mild to moderate Alzheimer's Disease (AD). These trials aimed at evaluating the efficacy and safety of the combination of galantamine and memantine versus galantamine alone.

RESULTS

Here, we report on the scope and projects of the DCN, the methods that were employed, the composition and flow within the diverse groups of patients and control persons and on the clinical and neuropsychological baseline characteristics of the group of 2,113 subjects who participated in the observational and clinical trials.

CONCLUSION

These data have an impact on the procedures for the early and differential clinical diagnosis of dementias, the current standard treatment of AD as well as on future clinical trials in AD.

Development of screening guidelines and clinical criteria for predementia Alzheimer's disease. The DESCRIPA Study

BACKGROUND

There is an urgent need to identify subjects with Alzheimer's disease (AD) in the predementia phase, but validated diagnostic approaches are currently lacking. In this paper, we present the background, design and methods of a study, which aims to develop clinical criteria for predementia AD. We also present baseline characteristics of the subjects included. The study was part of the multicentre DESCRIPA project, which is being conducted within the network of the European Alzheimer's Disease Consortium.

METHODS

Clinical criteria will be based on a prospective cohort study of non-demented subjects older than 55 years and referred to a memory clinic. At baseline, a number of markers and risk factors for AD were collected, including demographic variables, measures of performance in activities of daily living, cognitive, neuroimaging and genetic markers, and serum and cerebrospinal fluid markers. Subjects will be reassessed annually for 2-3 years, and we will evaluate which combination of variables best predicts AD-type dementia at follow-up.

RESULTS

Between 2003 and 2005, 881 subjects were included from 20 memory clinics. Subjects were on average 70.3 years old, and had 10.4 years of education. The average score on the Mini-Mental State Examination was 27.4.

Realistic expectations for treatment success in Alzheimer's disease

Alzheimer's disease (AD) is a progressive degenerative disease that warrants active management to delay or slow progression of its symptoms. The symptoms of AD encompass behavior and daily function as well as cognition, so clinicians should take a global view in the assessment of treatment success. Because there is currently no cure for AD, one cannot expect an initial cognitive improvement observed in the first few months of therapy to be sustained indefinitely. However, one should expect that the patient who is treated early and persistently with medication for AD will show less evidence of behavioral, functional, and cognitive deterioration over a period of time than one would expect in the absence of pharmacotherapy. Thus, treatment success includes not only short-term improvement of symptoms but also less decline over the long term. Determination of treatment success therefore also requires awareness of the typical progression of untreated AD. In this article we review the natural history of AD and evidence for the effectiveness of the treatments indicated for AD: donepezil, galantamine, rivastigmine, and memantine.

Longitudinal study on the relationship between symptomatology of dementia and levels of subjective burden and depression among family caregivers in memory clinic patients

The objective was to evaluate the course and severity of dementia-related symptoms and their relationship to caregivers' subjective burden and depression over time. Forty-five patients with dementia and their caregivers were followed over a period of 2 years. Patients' cognition, function, and behavioral/psychological symptoms were assessed by the Mini Mental State Examination, Syndrome Kurz Test, Geriatric Depression Screening scale, Instrumental Activities of Daily Living Scale, Physical Self Maintenance Scale, Behavioral Abnormalities in Alzheimer's Disease Rating Scale, and Nurses Observation Scale for Geriatric Patients. Caregivers' depression and subjective burden were evaluated by the Geriatric Depression Screening scale or Beck Depression Inventory and the Caregiver Burden Interview. Global dementia severity, functional impairment, and behavioral disturbances increased significantly over the 2-year observation period. Caregivers' burden remained stable, and severe depression decreased over time. There were significant associations between burden and dementia-related symptoms. For deficits in activities of daily living as well as behavioral disturbances, these associations became stronger over time. It was concluded that stage of dementia, functional deficits, and behavioral disturbances are important factors when evaluating the relationship between patients' symptoms and caregivers' well-being.

No effects of a combination of caregivers support group and memory training/music therapy in dementia patients from a memory clinic population

OBJECTIVES

To evaluate the impact of a combination of caregiver support group and memory training/music therapy in dementia patients on behavioural and psychological symptoms (BPSD) and caregiver burden compared to a control group.

METHOD

Eighteen patient-carer-dyads in the treatment group and 18 patient-carer-dyads as controls were studied in the setting of a memory clinic of a psychiatric university hospital over a period of 2 years. Controls were matched for age, gender, diagnosis, dementia severity, living arrangement and medication. The interventions were conducted once per week for 1 hour run by a clinical psychogeriatric team. Outcome measures were patients' cognitive and functional status as well as BPSD and caregivers subjective burden and depression measured by validated scales. Data were obtained 6, 12 and 24 months after baseline.

RESULTS

There were no significant differences between the intervention and control group neither after 6, 12 nor after 24 months treatment.

CONCLUSIONS

The lack of a positive impact in alleviating caregiver burden or BPSD after intensive psychological interventions may result from extensive care in the routine clinical management including individual counselling for patients and families. The effect of 'treatment as usual' needs to be taken into account when comparing an intervention and control group, as well as the dosage of the intervention.