Alzheimer's & Dementia

In 2011, the National Institute on Aging and Alzheimer's Association created separate diagnostic recommendations for the preclinical, mild cognitive impairment, and dementia stages of Alzheimer's disease. Scientific progress in the interim led to an initiative by the National Institute on Aging and Alzheimer's Association to update and unify the 2011 guidelines. This unifying update is labeled a “research framework” because its intended use is for observational and interventional research, not routine clinical care. In the National Institute on Aging and Alzheimer's Association Research Framework, Alzheimer's disease (AD) is defined by its underlying pathologic processes that can be documented by postmortem examination or in vivo by biomarkers. The diagnosis is not based on the clinical consequences of the disease (i.e., symptoms/signs) in this research framework, which shifts the definition of AD in living people from a syndromal to a biological construct. The research framework focuses on the diagnosis of AD with biomarkers in living persons. Biomarkers are grouped into those of β amyloid deposition, pathologic tau, and neurodegeneration [AT(N)]. This ATN classification system groups different biomarkers (imaging and biofluids) by the pathologic process each measures. The AT(N) system is flexible in that new biomarkers can be added to the three existing AT(N) groups, and new biomarker groups beyond AT(N) can be added when they become available. We focus on AD as a continuum, and cognitive staging may be accomplished using continuous measures. However, we also outline two different categorical cognitive schemes for staging the severity of cognitive impairment: a scheme using three traditional syndromal categories and a six‐stage numeric scheme. It is important to stress that this framework seeks to create a common language with which investigators can generate and test hypotheses about the interactions among different pathologic processes (denoted by biomarkers) and cognitive symptoms. We appreciate the concern that this biomarker‐based research framework has the potential to be misused. Therefore, we emphasize, first, it is premature and inappropriate to use this research framework in general medical practice. Second, this research framework should not be used to restrict alternative approaches to hypothesis testing that do not use biomarkers. There will be situations where biomarkers are not available or requiring them would be counterproductive to the specific research goals (discussed in more detail later in the document). Thus, biomarker‐based research should not be considered a template for all research into age‐related cognitive impairment and dementia; rather, it should be applied when it is fit for the purpose of the specific research goals of a study. Importantly, this framework should be examined in diverse populations. Although it is possible that β‐amyloid plaques and neurofibrillary tau deposits are not causal in AD pathogenesis, it is these abnormal protein deposits that define AD as a unique neurodegenerative disease among different disorders that can lead to dementia. We envision that defining AD as a biological construct will enable a more accurate characterization and understanding of the sequence of events that lead to cognitive impairment that is associated with AD, as well as the multifactorial etiology of dementia. This approach also will enable a more precise approach to interventional trials where specific pathways can be targeted in the disease process and in the appropriate people.

This report describes the public health impact of Alzheimer's disease, including incidence and prevalence, mortality rates, costs of care, and the overall impact on caregivers and society. It also examines in detail the financial impact of Alzheimer's on families, including annual costs to families and the difficult decisions families must often make to pay those costs. An estimated 5.4 million Americans have Alzheimer's disease. By mid‐century, the number of people living with Alzheimer's disease in the United States is projected to grow to 13.8 million, fueled in large part by the aging baby boom generation. Today, someone in the country develops Alzheimer's disease every 66 seconds. By 2050, one new case of Alzheimer's is expected to develop every 33 seconds, resulting in nearly 1 million new cases per year. In 2013, official death certificates recorded 84,767 deaths from Alzheimer's disease, making it the sixth leading cause of death in the United States and the fifth leading cause of death in Americans age ≥65 years. Between 2000 and 2013, deaths resulting from stroke, heart disease, and prostate cancer decreased 23%, 14%, and 11%, respectively, whereas deaths from Alzheimer's disease increased 71%. The actual number of deaths to which Alzheimer's disease contributes is likely much larger than the number of deaths from Alzheimer's disease recorded on death certificates. In 2016, an estimated 700,000 Americans age ≥65 years will die with Alzheimer's disease, and many of them will die because of the complications caused by Alzheimer's disease. In 2015, more than 15 million family members and other unpaid caregivers provided an estimated 18.1 billion hours of care to people with Alzheimer's and other dementias, a contribution valued at more than $221 billion. Average per‐person Medicare payments for services to beneficiaries age ≥65 years with Alzheimer's disease and other dementias are more than two and a half times as great as payments for all beneficiaries without these conditions, and Medicaid payments are 19 times as great. Total payments in 2016 for health care, long‐term care and hospice services for people age ≥65 years with dementia are estimated to be $236 billion. The costs of Alzheimer's care may place a substantial financial burden on families, who often have to take money out of their retirement savings, cut back on buying food, and reduce their own trips to the doctor. In addition, many family members incorrectly believe that Medicare pays for nursing home care and other types of long‐term care. Such findings highlight the need for solutions to prevent dementia‐related costs from jeopardizing the health and financial security of the families of people with Alzheimer's and other dementias.

This article describes the public health impact of Alzheimer's disease (AD), including incidence and prevalence, mortality and morbidity, use and costs of care, and the overall impact on caregivers and society. The Special Report examines the use of brief cognitive assessments by primary care physicians as a tool for improving early detection of dementia. An estimated 5.8 million Americans have Alzheimer's dementia. By mid‐century, the number of people living with Alzheimer's dementia in the United States may grow to 13.8 million, fueled in large part by the aging baby boom generation. In 2017, official death certificates recorded 121,404 deaths from AD, making AD the sixth leading cause of death in the United States and the fifth leading cause of death among Americans age ≥65 years. Between 2000 and 2017, deaths resulting from stroke, heart disease, and prostate cancer decreased, whereas reported deaths from AD increased 145%. In 2018, more than 16 million family members and other unpaid caregivers provided an estimated 18.5 billion hours of care to people with Alzheimer's or other dementias. This care is valued at nearly $234 billion, but its costs extend to family caregivers' increased risk for emotional distress and negative mental and physical health outcomes. Average per‐person Medicare payments for services to beneficiaries age ≥65 years with Alzheimer's or other dementias are more than three times as great as payments for beneficiaries without these conditions. Total payments in 2019 for health care, long‐term care and hospice services for people age ≥65 years with dementia are estimated to be $290 billion. Early detection of Alzheimer's offers numerous medical, emotional and financial benefits—benefits that accrue to affected individuals and their families as well as to society at large. Alzheimer's Association surveys regarding brief cognitive assessments for detection of dementia found that while a large majority of seniors and primary care physicians say the assessments are important, only half of seniors have received an assessment, and only 16 percent of seniors receive regular cognitive assessments. Many educational opportunities exist to facilitate increased use of brief cognitive assessments in the primary care setting.

There is increasing evidence that subjective cognitive decline (SCD) in individuals with unimpaired performance on cognitive tests may represent the first symptomatic manifestation of Alzheimer's disease (AD). The research on SCD in early AD, however, is limited by the absence of common standards. The working group of the Subjective Cognitive Decline Initiative (SCD‐I) addressed this deficiency by reaching consensus on terminology and on a conceptual framework for research on SCD in AD. In this publication, research criteria for SCD in pre‐mild cognitive impairment (MCI) are presented. In addition, a list of core features proposed for reporting in SCD studies is provided, which will enable comparability of research across different settings. Finally, a set of features is presented, which in accordance with current knowledge, increases the likelihood of the presence of preclinical AD in individuals with SCD. This list is referred to as SCD plus.

An estimated 47 million people worldwide are living with dementia in 2015, and this number is projected to triple by 2050. In the absence of a disease‐modifying treatment or cure, reducing the risk of developing dementia takes on added importance. In 2014, the World Dementia Council (WDC) requested the Alzheimer's Association evaluate and report on the state of the evidence on modifiable risk factors for cognitive decline and dementia. This report is a summary of the Association's evaluation, which was presented at the October 2014 WDC meeting. The Association believes there is sufficient evidence to support the link between several modifiable risk factors and a reduced risk for cognitive decline, and sufficient evidence to suggest that some modifiable risk factors may be associated with reduced risk of dementia. Specifically, the Association believes there is sufficiently strong evidence, from a population‐based perspective, to conclude that regular physical activity and management of cardiovascular risk factors (diabetes, obesity, smoking, and hypertension) reduce the risk of cognitive decline and may reduce the risk of dementia. The Association also believes there is sufficiently strong evidence to conclude that a healthy diet and lifelong learning/cognitive training may also reduce the risk of cognitive decline.

This article describes the public health impact of Alzheimer's disease (AD), including incidence and prevalence, mortality rates, costs of care, and the overall impact on caregivers and society. The Special Report examines how the use of biomarkers may influence the AD diagnostic process and estimates of prevalence and incidence of the disease. An estimated 5.5 million Americans have Alzheimer's dementia. By mid‐century, the number of people living with Alzheimer's dementia in the United States is projected to grow to 13.8 million, fueled in large part by the aging baby boom generation. Today, someone in the country develops Alzheimer's dementia every 66 seconds. By 2050, one new case of Alzheimer's dementia is expected to develop every 33 seconds, resulting in nearly 1 million new cases per year. In 2014, official death certificates recorded 93,541 deaths from AD, making AD the sixth leading cause of death in the United States and the fifth leading cause of death in Americans age ≥65 years. Between 2000 and 2014, deaths resulting from stroke, heart disease, and prostate cancer decreased 21%, 14%, and 9%, respectively, whereas deaths from AD increased 89%. The actual number of deaths to which AD contributes is likely much larger than the number of deaths from AD recorded on death certificates. In 2017, an estimated 700,000 Americans age ≥65 years will have AD when they die, and many of them will die because of the complications caused by AD. In 2016, more than 15 million family members and other unpaid caregivers provided an estimated 18.2 billion hours of care to people with Alzheimer's or other dementias. This care is valued at more than $230 billion. Average per‐person Medicare payments for services to beneficiaries age ≥65 years with Alzheimer's or other dementias are more than three times as great as payments for beneficiaries without these conditions, and Medicaid payments are more than 23 times as great. Total payments in 2017 for health care, long‐term care, and hospice services for people age ≥65 years with dementia are estimated to be $259 billion. In recent years, efforts to develop and validate AD biomarkers, including those detectable with brain imaging and in the blood and cerebrospinal fluid, have intensified. Such efforts could transform the practice of diagnosing AD from one that focuses on cognitive and functional symptoms to one that incorporates biomarkers. This new approach could promote diagnosis at an earlier stage of disease and lead to a more accurate understanding of AD prevalence and incidence.