Projections of Alzheimer's disease in the United States and the public health impact of delaying disease onset

When should functional neuroimaging techniques be used in the diagnosis and management of Alzheimer's dementia? A decision analysis

BACKGROUND

Functional neuroimaging, including positron emission tomography (PET), has been proposed for use in diagnosing Alzheimer's disease-related dementia (AD).

OBJECTIVE

The objective of this study was identify the circumstances under which PET scanning for the diagnosis of AD maximizes health outcomes.

METHODS

A Markov-model-based decision analysis was conducted using estimates derived from the literature on AD epidemiology, the accuracy of PET, and donepezil treatment efficacy. The target population for the analysis was assumed to be US men and women who either have mild AD or are asymptomatic but at an elevated risk of developing AD owing to disease in a first-degree relative (parent or sibling). The time horizon was the patient lifetime. We compared treatment 1) based on an American Academy of Neurology (AAN) clinical evaluation either alone; 2) in combination with PET scanning; or 3) empirically based on a family history. Outcomes measures were life expectancy, quality-adjusted life-years (QALYs), and (severe) dementia-free life expectancy (SDFLE).

RESULTS

For both patient populations, treating all patients based on an AAN evaluation without further testing using PET resulted in the greatest gains in life expectancy, QALYs, and SDFLEs. PET-based testing was the second preferred strategy compared to no intervention. The rankings of the strategies were sensitive to severity of treatment complications: analyses of hypothetical treatments with the potential for severe complications indicated that testing was preferred if the treatment was effective but had moderate complications.

CONCLUSIONS

These results suggest that current treatments, which are relatively benign and may slow progression of disease, should be offered to patients who are identified as having AD based solely on an AAN clinical evaluation. A clinical evaluation that includes functional neuroimaging based testing will be warranted, however, when new treatments that are effective at slowing disease progression but have the potential for moderate to severe complications become available.

Cost-effectiveness of PET in the diagnosis of Alzheimer disease

PURPOSE

To evaluate the cost-effectiveness of positron emission tomography (PET) in the diagnosis of Alzheimer disease (AD) in community-dwelling patients with mild or moderate dementia who present to specialized AD centers.

MATERIALS AND METHODS

A decision-analytic model was used to compare costs and quality-adjusted life years (QALYs) associated with strategies involving single photon emission computed tomography (SPECT), dynamic susceptibility-weighted contrast material-enhanced magnetic resonance (MR) imaging, and PET as functional imaging adjuncts to the standard clinical work-up. Sensitivity analyses were performed to examine changes in test characteristics, health-related quality-of-life survey instruments, therapeutic effectiveness, and treatment rules.

RESULTS

The use of PET to confirm the results of the standard clinical work-up cost more but yielded fewer benefits than a strategy in which dynamic susceptibility-weighted contrast-enhanced MR imaging was substituted for the typically performed structural computed tomography. This relationship remained stable in scenarios in which standard diagnostic work-up accuracy, drug treatment effectiveness, and version of the Health Utilities Index were altered. Dynamic susceptibility-weighted contrast-enhanced MR imaging cost US dollars 598800 per QALY gained (range, US dollars 74400 to US dollars 1.9 million per QALY), compared with the cost of the standard diagnostic work-up. Treating all patients with dementia was the dominant imaging strategy, except when side effects in patients with non-AD-related dementia were modeled. In all scenarios, SPECT yielded fewer benefits than other strategies at a higher cost.

CONCLUSION

PET may have high diagnostic accuracy, but adding it to the standard diagnostic regimen at AD clinics would yield limited, if any, benefits at very high costs.

Application of capture-recapture methodology to estimate the prevalence of dementia in South Carolina

PURPOSE

The purpose of this study was to estimate the prevalence of dementia in individuals 65 years of age and older in the state of South Carolina using capture-recapture methodology.

METHODS

We linked data from the Department of Mental Health admissions, inpatient admissions, and emergency room visits. Separate log-linear models were used to obtain estimates of the underascertainment-corrected prevalence of dementia in twelve age-gender-race subgroups, which were summed to estimate the prevalence of dementia in the total population.

RESULTS

We found an overall prevalence of dementia of 14% in South Carolina for persons 65 years of age and older using capture-recapture methodology. This estimate of persons with dementia is 25% higher than the identified cases of dementia in the South Carolina Alzheimer's Disease Registry (10.5%).

CONCLUSIONS

Although capture-recapture methods are prone to limitations, they can be used to more accurately estimate the prevalence of dementia in a geographic area.

Depression in Alzheimer's disease: heterogeneity and related issues

Several studies have demonstrated that the great majority of Alzheimer's disease (AD) patients suffer "noncognitive" neuropsychiatric symptoms. Depression is one of the most frequent neuropsychiatric comorbidities of AD. Affecting up to 50% of AD patients, depression in AD is associated with serious negative consequences for patients and their caregivers. Yet available studies on the natural course, etiology, and treatment of depression in AD have been few and equivocal. Heterogeneity in research methodology and etiology of depression in AD might have contributed to inconsistent findings across studies. Recently, the National Institute of Mental Health (NIMH) convened the Depression of Alzheimer's Disease Workgroup, which proposed provisional diagnostic criteria for depression of Alzheimer's Disease (NIMH-dAD). These criteria may provide a framework for future studies to clarify the unresolved issues in nosology, etiology, and treatment of depression in AD. A longitudinal cohort study of depression in incident AD cases may provide further syndrome refinement that would facilitate investigation of the etiology and treatment of depression in AD.

Interventions to prevent aspiration pneumonia in older adults: a systematic review

A systematic review was conducted to assess the effectiveness of the following interventions for prevention of aspiration pneumonia (AP) in older adults: compensatory strategy/positioning changes, dietary interventions, pharmacologic therapies, oral hygiene, and tube feeding. Data sources included a key word search of the MEDLINE, EMBASE, Cochrane Library, CINAHL, and HealthSTAR databases and hand searches of six journals. Reference lists of relevant primary and review articles were searched. Studies included were randomized, controlled trials (RCTs) enrolling adults aged 65 and older at risk of and assessed for AP. Two investigators extracted data on population, intervention, outcomes, and methodological quality. Of the 17 identified RCTs, eight met the selection criteria, two addressed dietary management or compensatory swallowing, two assessed pharmacological therapies, one assessed oral hygiene, and three assessed tube feeding. None of the eight trials reported use of blinding, and allocation concealment was unclear in five. Use of amantadine prevented pneumonia in one trial of nursing home residents. The antithrombotic agent cilostazol prevented AP in another trial but resulted in excessive bleeding. Insufficient data exist to determine the effectiveness of positioning strategies, modified diets, oral hygiene, feeding tube placement, or delivery of food in preventing AP. Considering how common the problem of AP is in older adults, larger, high-quality RCTs on the effectiveness of preventive interventions are warranted.

Early Intervention Is Key to Successful Management of Alzheimer Disease

Because of the huge healthcare burden associated with Alzheimer disease (AD) and the increased lifespan in many industrialized countries, the costs associated with AD are expected to reach astronomical proportions in the next 50 years. Diagnosis, treatment and follow-up of AD patients from the earliest stage possible will reduce healthcare costs and increase quality of life. Indeed, progress in our clinical knowledge of AD has led to more reliable diagnostic criteria and diagnostic accuracy, and research efforts are expanding to uncover the earliest manifestations and even the presymptomatic phases of the disease. The initiating and propagating pathologic processes and the anatomic location of the earliest changes will become new targets of research and therapeutic development. The proposed precursor to AD, mild cognitive impairment, is currently under investigation as a possible therapeutic starting point. This paper reviews our current understanding of the early pathology and clinical manifestations associated with mild cognitive impairment and early AD. A discussion of the latest diagnostic techniques as well as promising therapeutic targets for early intervention also will be included.

Vascular factors and cognition: toward a prevention of dementia?

High blood pressure is a known risk factor for stroke and dementia. However, very little is known about the prevention of dementia by lowering blood pressure. Perindopril pROtection aGainst REcurrent Stroke Study (PROGRESS) was designed to determine the effects of an angiotensin-converting enzyme (ACE) inhibitor-based blood pressure-lowering regimen on the risk of stroke among individuals with a prior stroke or transient ischaemic attack (TIA). One of the important aims of the study was to test the hypothesis that treatment would reduce the incidence of dementia and cognitive decline. A total of 6105 patients were randomized to active treatment or placebo. Active treatment comprised perindopril for all participants, and indapamide for those with neither a specific indication for, nor a contraindication to, a diuretic. Dementia was diagnosed according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition. Cognitive decline was defined as a drop of 3 points or more on the Mini-Mental State Examination (MMSE) between baseline and final follow-up. During a median follow-up of 3.9 years, dementia was diagnosed in 410 patients and cognitive decline in 610. Active treatment reduced the risk of cognitive decline (risk reduction [RR] 19%; 95% confidence interval [CI], 4-32; P = 0.01] but there was no clear reduction in the risk of dementia (RR, 12%; 95% CI, -8-28; P = 0.2]). The RR for cognitive outcomes preceded by a recurrent stroke was 34% (95% CI, 3-55; P = 0.03) for dementia and 45% (95% CI, 21-61; P = <0.001) for cognitive decline. Among individuals with a history of stroke or TIA, blood pressure-lowering treatment reduced the risk of cognitive decline by about one fifth. Cognitive decline and dementia associated with recurrent stroke during follow-up were each reduced by between one third and one half. These findings provide further support for the recommendation that blood pressure lowering with perindopril and indapamide be considered for all patients with cerebrovascular disease.

A review of rivastigmine: a reversible cholinesterase inhibitor

BACKGROUND

Rivastigmine tartrate is a reversible cholinesterase inhibitor indicated for the symptomatic treatment of mild to moderate dementia. It was approved by the US Food and Drug Administration for the treatment of Alzheimer's disease (AD) on April 21, 2000.

OBJECTIVE

The purpose of this review was to summarize the background on dementia of the Alzheimer type and the pharmacokinetic properties, efficacy and tolerability profiles, clinical applications, adverse effects (AEs), drug interactions, and pharmacoeconomics of rivastigmine.

METHODS

A literature search was conducted using MEDLINE (1995-2002), EMBASE Geriatrics and Gerontology (1995-2002), the National Institutes of Health Alzheimer's Disease Education and Resource Center Combined Health Information Database, and Google. Search terms included rivastigmine, Exelon, ENA 713, and ENA-713. The bibliographies of retrieved articles also were searched for relevant articles.

RESULTS

In clinical trials, rivastigmine has improved or maintained cognitive function, global function (ie, activities of daily living [ADLs]), and behavior in patients with mild to moderate AD for up to 52 weeks. AEs are generally mild to moderate and primarily affect the gastrointestinal (GI) tract. Clinically significant drug interactions with rivastigmine have thus far not been reported. Treatment with rivastigmine for up to 2 years may reduce the cost of caring for patients with AD. Cost savings are minimal during the first year, particularly for those with mild disease, but increase during the second year of treatment. Cost savings occur earlier for those with moderate AD. Most savings are realized from a delay in the need for institutionalization.

CONCLUSIONS

Rivastigmine has been shown to improve or maintain patients' performance in 3 major domains: cognitive function, global function (ADLs), and behavior. The efficacy and tolerability of rivastigmine have been proved by numerous clinical trials, with the most prominent AE being GI irritation.

Pathology and pathways of Alzheimer's disease with an update on new developments in treatment

As our understanding of the complex pathology of Alzheimer's disease improves, more targets for therapy emerge. These include the actions of beta amyloid, the inflammatory cascade, pathobiology of tau proteins' conversion to neurofibrillary tangles, oxidative neuronal damage, and neurotransmitter depletion. Many agents now under investigation target the early stages of the disease process, aiming to prevent or slow the development of symptoms. This article reviews the current understanding of the course and pathology of Alzheimer's disease as it relates to emerging therapies, then summarizes some promising current research directions in primary prevention, secondary prevention, and treatment.

Neuroimaging in Alzheimer disease: an evidence-based review

Current clinical criteria (DSM-IIIR and NINCDS-ADRDA) for the diagnosis of dementia and AD are reliable; however, these criteria remain to be validated by clinicians of different levels of expertise at different clinical settings. Structural neuroimaging has an important role in initial evaluation of dementia for ruling out potentially treatable causes. Although CT is the appropriate choice when brain tumors, subdural hematoma, or normal pressure hydrocephalus is suspected, MR imaging is more sensitive to the white-matter changes in vascular dementia. The diagnostic accuracy of PET, SPECT, 1H MRS, and MR volumetry of the hippocampus for distinguishing patients with AD from healthy elderly individuals is comparable to the accuracy of a pathologically confirmed clinical diagnosis. Sensitivity of PET for distinguishing patients with dementia with Lewy bodies from AD, however, is higher than that of clinical evaluation; similarly, SPECT and 1H MRS may be adjuncts to clinical evaluation for distinguishing patients with frontotemporal dementia from those with AD. Neuroimaging is valuable in predicting future development of AD in patients with MCI and in carriers of the ApoE epsilon 4 allele who are at a higher risk of developing AD than are cognitively normal elderly individuals. Quantitative MR techniques (e.g., MR volumetry, DWI, magnetization transfer MR imaging, and 1H MRS) and PET are sensitive to the structural and functional changes in the brains of patients with MCI, and hippocampal volumes on MR imaging are associated with future development of AD in these individuals. PET is also sensitive to the regional metabolic decline in the brains of carriers of the ApoE epsilon 4 allele. The longitudinal decrease of whole brain and hippocampal volumes on MR imaging, NAA levels on 1H MRS, cerebral glucose metabolism on PET, and cerebral blood flow on SPECT are associated with rate of cognitive decline in patients with AD. These neuroimaging markers may be useful for monitoring symptomatic progression in groups of patients with AD for drug trials. Furthermore, antemortem MR-based hippocampal volumes correlate with the pathologic stage of AD, and the rate of hippocampal volume loss on MR imaging correlates with clinical disease progression in the cognitive continuum from normal aging to MCI and to AD. Hence, as an in vivo correlate of pathologic involvement, structural imaging measures are potential surrogate markers for disease progression in patients with established AD and in patients with prodromal AD, who will benefit most from disease-modifying therapies underway.

Which Alzheimer patients are at risk for rapid cognitive decline?

In the current study of 1062 Alzheimer's disease (AD) patients, we employed receiver operating characteristic curve analysis to identify characteristics of patients at increased risk for rapid cognitive decline. The patients are participants at one of the nine Alzheimer's Disease Research Centers of California. Rapid decline was defined as a 3-point or greater loss on the Mini-Mental State Examination (MMSE) per year, post visit. The independent variables were age at clinic visit, age at symptom onset of AD, MMSE at patient visit, years of education, gender, ethnicity, living arrangement, presence of aphasia, delusions, hallucinations, and extrapyramidal signs. Receiver operating characteristic curve analysis indicated that AD patients presenting with moderate to severe aphasia, age at clinic visit of 75 years or less, and an MMSE greater than 7 were at increased risk for rapid cognitive decline. This information could help clinicians target these patients for pharmacologic interventions, facilitate long-term care planning, and potentially create savings by delaying or stabilizing the course of the disease.

Cost of illness of Alzheimer's disease: how useful are current estimates?

PURPOSE

The goal of this literature review was to determine the validity and policy relevance of recent estimates from many countries of Alzheimer's disease (AD) costs.

DESIGN AND METHODS

We searched Medline and other databases for English-language peer-reviewed journals on total, direct, indirect, and per case cost of AD that used 1985-2000 data. We adjusted costs of U.S. studies for inflation. We adjusted non-U.S. studies by that country's medical cost inflation rate and purchasing power parity (PPP).

RESULTS

Of 71 studies identified, 21 met all criteria for inclusion. Annual inflation adjusted U.S. total costs of AD varied from $5.6 billion to $88.3 billion. AD total per case (direct and indirect) costs varied from $1,500 to $91,000; indirect/family costs varied from $3,700 to $21,000. Among non-U.S. studies, AD annual adjusted per case costs varied from PPP $2,300 to PPP $30,000. Cost variation was due to diverse study methods, data sources, services included, and lack of clear differentiation between cost of AD and cost of caring for people with AD.

IMPLICATIONS

The cost of AD is high, although reliable estimates are not available. Costs are likely to rise given expected demographic shifts in all countries. The widely variable cost estimates call into question the real costs of Alzheimer's disease and their applicability to policy initiatives.

The role of insulin resistance in the pathogenesis of Alzheimer's disease: implications for treatment

An emerging body of evidence suggests that an increased prevalence of insulin abnormalities and insulin resistance in Alzheimer's disease may contribute to the disease pathophysiology and clinical symptoms. It has long been known that insulin is essential for energy metabolism in the periphery. In the past 2 decades, convergent findings have begun to demonstrate that insulin also plays a role in energy metabolism and other aspects of CNS function. Investigators reported 20 years ago that insulin and insulin receptors were densely but selectively expressed in the brain, including the medial temporal regions that support the formation of memory. It has recently been demonstrated that insulin-sensitive glucose transporters are localised to the same regions supporting memory and that insulin plays a role in memory functions. Collectively, these findings suggest that insulin may contribute to normal cognitive functioning and that insulin abnormalities may exacerbate cognitive impairments, such as those associated with Alzheimer's disease. Insulin may also play a role in regulating the amyloid precursor protein and its derivative beta-amyloid (Abeta), which is associated with senile plaques, a neuropathological hallmark of Alzheimer's disease. It has been proposed that insulin can accelerate the intracellular trafficking of Abeta and interfere with its degradation. These findings are consistent with the notion that insulin abnormalities may potentially influence levels of Abeta in the brains of patients with Alzheimer's disease. The increased occurrence of insulin resistance in Alzheimer's disease and the numerous mechanisms through which insulin may affect clinical and pathological aspects of the disease suggest that improving insulin effectiveness may have therapeutic benefit for patients with Alzheimer's disease. The thiazolidinedione rosiglitazone has been shown to have a potent insulin-sensitising action that appears to be mediated through the peroxisome proliferator-activated receptor-gamma (PPAR-gamma). PPAR-gamma agonists, such as rosiglitazone, also have anti-inflammatory effects that may be of therapeutic benefit in patients with Alzheimer's disease. This review presents evidence suggesting that insulin resistance plays a role in the pathophysiology and clinical symptoms of Alzheimer's disease. Based on this evidence, we propose that treatment of insulin resistance may reduce the risk or retard the development of Alzheimer's disease.

Palliative Excellence in Alzheimer Care Efforts (PEACE): a program description

Hospice is the standard method for providing quality end-of-life care in the United States. However, studies reveal that persons with dementia are infrequently referred to hospice, that barriers exist to increasing hospice utilization in this population, and that patients with dementia would benefit from hospice or hospice-like services earlier in the disease course. The Palliative Excellence in Alzheimer Care Efforts (PEACE) program responds to these deficiencies, striving to improve end-of-life care of persons with dementia and to integrate palliative care into the primary care of patients with dementia throughout the course of the illness. The PEACE program is a disease management model for dementia that incorporates advance planning, patient-centered care, family support, and a palliative care focus from the diagnosis of dementia through its terminal stages. PEACE is coordinated through the primary care geriatrics practice of the University of Chicago. Patients and caregivers are interviewed every 6 months for 2 years, and a postdeath interview is conducted with caregivers. These interviews assess care domains important for the optimal care of persons with dementia and their caregivers. A nurse coordinator reviews interviews and provides feedback to physicians, facilitating enhanced individual care and continuous quality improvement for the practice. Initial feedback suggests patients have adequate pain control, satisfaction with quality of care, appropriate attention to prior stated wishes, and death occurring in the patient's location of choice. Families voiced similar high marks regarding quality of care. This program demonstrates an innovative model of providing quality palliative care for dementia patients and their caregivers.

Cost of anemia in the elderly

As the aging population and the incidence of age-related health conditions increase, the cost of healthcare is also expected to rise. Anemia commonly occurs in the elderly, and is associated with a number of health conditions such as falls, weakness, and immobility. It can also lead to more-serious complications such as cardiovascular and neurological impairments. Consequently, anemia can have a significant effect on healthcare requirements and healthcare expenditure. Research is needed into the opportunity to reduce costs.

Special care for persons with Alzheimer's disease and related dementias in Virginia adult care residences

Designing supportive care for persons with Alzheimer's disease and related dementias in residential care is one of the most challenging issues facing researchers, policymakers, and facility administrators. To gain a better knowledge of the types of special care offered by adult care residences (ACRs) and assisted living facilities, the results of a survey of all licensed ACRs in the state of Virginia are presented. Examined are the facilities with special care units (SCUs) and special programs (SPs), the organizational characteristics of facilities that offer special care, the characteristics of existing SCUs and SPs, and the opinions of owners/operators on the elements needed for establishing these units and programs. The discussion focuses on improvements needed within special care and the implications of the views of owners/operators about special care.

Trends in dementia mortality from two National Mortality Followback Surveys

The National Center for Health Statistics conducted National Mortality Followback Surveys (NMFS) in 1986 and 1993. The next-of-kin's report of a physician's diagnosis of AD before death and a listing of AD or other dementia as the underlying cause increased significantly among women but remained stable among men. Currently, AD is among the top 10 leading causes of death in elderly white men and women in the United States.

Recent perspectives on active life expectancy for older women

This article provides a critical review of recent active life expectancy literature, describing trends of special interest to women. We review findings from leading perspectives used to study life expectancy and active life expectancy, including gender, racial and socioeconomic differences, disease-specific effects, and biodemography. We examine three competing theories of population health that frame active life expectancy research-compression of morbidity, expansion of morbidity, and dynamic equilibrium-concluding there is support for both the compression of morbidity and dynamic equilibrium theories. Policy implications for women include a greater understanding of the role of education and racial and ethnic diversity in active life trends, and an increased public policy emphasis on prevention and treatment of chronic disease, together with adoption of more healthy lifestyles.

Can estrogen play a significant role in the prevention of Alzheimer's disease?

In women the abrupt decline estrogen levels at menopause may be associated with cognitive deficits and increased risk for Alzheimer's disease (AD); estrogen replacement therapy may reduce this risk. Animal studies indicate that estrogen modulates neurotransmitter systems, regulates synaptogenesis, and is neuroprotective. These beneficial effects occur in brain areas critical to cognitive function and involved in AD. Reduced estrogen levels can compromise neuronal function and survival. Estrogen replacement therapy can reverse cognitive deficits associated with low estrogen levels and may reduce the risk of AD. However, clinical trials for estrogen replacement in the treatment of AD have produced ambiguous results. Initial, small, open-label and double blind clinical trials indicated improved cognitive function in women with AD. Recent large trials failed to show a beneficial effect for long-term estrogen replacement for women with AD. There are several variables that could affect these results, such as genetic factors, time between estrogen loss and replacement, extent and types of AD pathology, and other environmental and health factors. Presently large prospective studies are being conducted as the National Institutes of Health in the Women's Health Initiative and the Preventing Postmenopausal Memory Loss and Alzheimer's with Replacement Estrogens studies to provide a better assessment of the role of estrogen for age related health issues, including dementia.

Medicinal chemistry approaches for the treatment and prevention of Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia, which is characterised by progressive deterioration of memory and higher cortical functions that ultimately result in total degradation of intellectual and mental activities. Modern strategies in the search of new therapeutic approaches are based on the morphological and biochemical characteristics of AD, and focused on following directions: agents that compensate the hypofunction of cholinergic system, agents that interfere with the metabolism of beta-amyloid peptide, agents that protect nerve cells from toxic metabolites formed in neurodegenerative processes, agents that activate other neurotransmitter systems that indirectly compensate for the deficit of cholinergic functions, agents that affect the process of the formation of neurofibrillary tangles, anti-inflammatory agents that prevent the negative response of nerve cells to the pathological process. The goal of the present review is the validation and an analysis from the point of view of medicinal chemistry of the principles of the directed search of drugs for the treatment and prevention of AD and related neurodegenerative disorders. It is based on systematization of the data on biochemical and structural similarities in the interaction between physiologically active compounds and their biological targets related to the development of such pathologies. The main emphasis is on cholinomimetic, anti-amyloid and anti-metabolic agents, using the data that were published during the last 3 to 4 years, as well as the results of clinical trials presented on corresponding websites.

Mild cognitive impairment: prevalence, prognosis, aetiology, and treatment

Mild cognitive impairment (MCI) is a recently described syndrome that is currently thought of as a transition phase between healthy cognitive ageing and dementia. Although this notion seems to be reasonable, the general nature of the term MCI--including its many definitions--makes accurate accounting of the prevalence, prognosis, and potential benefit from treatment somewhat difficult. The differences in cognitive profile and clinical progression among individuals with MCI are generally recognised. However, recent evidence also suggests that the aetiological heterogeneity among individuals with MCI could be greater than previously reported. For example, cerebrovascular disease seems to be underestimated as a potential cause of MCI. In this review, I attempt to recognise workable definitions of MCI to discuss the prevalence, pathophysiology, prognosis, and possibilities for treatment of this disorder.

Informal caregiving for chronic lung disease among older Americans

STUDY OBJECTIVE

To obtain nationally representative estimates of the additional time, and related cost, of unpaid family caregiving (informal caregiving) associated with chronic lung disease among older Americans.

DESIGN

Multivariable regression models using data from the 1993 Asset and Health Dynamics Study, a nationally representative survey of people > or = 70 years old (n = 7,443).

PARTICIPANTS

National population-based sample of the community-dwelling elderly.

MEASUREMENTS

Weekly hours of informal caregiving, and imputed cost of caregiver time, for community-dwelling elderly who reported the following: (1) no lung disease, (2) lung disease without associated activity limitations, or (3) lung disease with associated activity limitations.

RESULTS

After adjusting for sociodemographic variables, potential caregiver network, and comorbid conditions, individuals with chronic lung disease and associated activity limitations (n = 403) received an additional 5.1 h/wk of informal care when compared to those with no lung disease (n = 6,593; p < 0.001). The associated additional yearly cost of informal care per case was $2,200 USD. This represents a national annual cost of informal caregiving for chronic lung disease of > $2 billion USD.

CONCLUSIONS

The quantity and associated economic cost of informal caregiving for elderly individuals with chronic lung disease are substantial. These costs to families and society must be accounted for if the full societal costs of chronic lung disease are to be calculated. Pulmonary physicians caring for elderly individuals with chronic lung disease should be mindful of the importance of informal care for the well-being of their patients, as well as the potential for significant burden on those (often elderly) individuals providing the care.

Alzheimer's disease patients' and caregivers' capacity, competency, and reasons to enroll in an early-phase Alzheimer's disease clinical trial

OBJECTIVES

To examine the capacity, competency, and reasons for enrolling of patients with Alzheimer's disease (AD) and of their caregivers in an early phase AD clinical trial.

DESIGN

Interviews were conducted with patients with AD, nondemented older persons, and caregivers.

SETTING

Participants' homes.

PARTICIPANTS

Fifteen patients with mild to moderate AD, 15 age- and education-matched nondemented older persons, and 15 patient caregivers.

MEASUREMENTS

Capacity was measured using the MacArthur Competency Assessment Tool for Clinical Research (MacCAT-CR); a study coordinator who reviewed audiotapes of the capacity interviews judged competency, and the reasons for a decision were determined by coding the capacity interviews.

RESULTS

On all measures except the ability to make a choice, patients performed worse than controls (understanding: z = 3.2, P =.001; appreciation: z = 2.8, P =.005; reasoning: z = 3.5, P =.0005), and caregivers (understanding: z = 3.8, P =.0002; appreciation: z = 3.0, P =.003; reasoning: z = 3.6, P =.0003). Using the controls' performance to set psychometric criteria to define capacity, the proportions of patients with adequate understanding, appreciation, and reasoning were six of 15 (40%), three of 15 (20%), and five of 15 (33%). All caregivers and nine of the 15 (60%) patients were competent. Reasons for enrolling typically featured the potential benefit to the patients' health or well-being and altruism that was expressed as a desire to help other patients and their families or a desire to contribute to scientific knowledge.

CONCLUSIONS

The MacCAT-CR, in particular its understanding scale, is a reliable and valid way to assess patient capacity and competency to enroll in an early-phase clinical trial. Although many patients have significant impairments in their capacity, some mild-stage patients are competent. Reasons for enrolling in an early-phase trial blend an expectation of therapeutic benefit and a desire to help others.

Diagnose and treat mild to moderate Alzheimer's disease

Early diagnosis and treatment of Alzheimer's disease, a chronic, debilitating disease, can delay cognitive, functional, and behavioral declines in afflicted patients. Here, learn how to diagnose and manage the disease with the latest pharmacologic approaches. Early diagnosis and treatment, coupled with caregiver support, can delay nursing home placement, improving patient well-being.

Research agenda for understanding Alzheimer disease in diverse populations: work group on cultural diversity, Alzheimer's association

The emerging evidence of ethnic variations in apolipoprotein polymorphism and Alzheimer disease risk shows that one cannot generalize findings based on a single cultural group too broadly ( Tang et al., 2001). Presence of one apolipoprotein E epsilon 4 allele is a stronger risk factor for Alzheimer disease in whites and Asians than in blacks ( Farrer et al., 1997). Environmental or genetic cofactors may modulate the effects of epsilon 4 on beta-amyloid metabolism differently in different subpopulations ( Shadlen, 1998). Recognizing this, the Alzheimer's Association has extended its goals to strengthen the scientific information base on the interactions of population diversity and Alzheimer disease heterogeneity ( NIA, 1998). This new focus is timely since minority elderly are the most rapidly increasing segment of the elderly population ( Lilienfeld and Perl, 1994, Brookmeyer et al., 1998). In this article, the authors highlight recent progress in research on Alzheimer disease among culturally diverse populations with a special emphasis on gaps in the knowledge base. The authors recommend four priorities for future Alzheimer disease research: (1) determine whether genetic causative factors interact differently in different populations; (2) reexamine the nature and role of cerebral ischemia and infarction and variations in symptom severity of Alzheimer disease; (3) explore the interaction of genes and environmental influences that are protective against Alzheimer disease; and (4) recruit and enroll ethnically diverse subjects in Alzheimer disease clinical trials.

The public health impact of Alzheimer's disease, 2000-2050: potential implication of treatment advances

Recent developments in basic research suggest that therapeutic breakthroughs may occur in Alzheimer's disease treatment over the coming decades. To model the potential magnitude and nature of the effect of these advances, historical data from congestive heart failure and Parkinson's disease were used. Projections indicate that therapies which delay disease onset will markedly reduce overall disease prevalence, whereas therapies to treat existing disease will alter the proportion of cases that are mild as opposed to moderate/severe. The public health impact of such changes would likely involve both the amount and type of health services needed. Particularly likely to arise are new forms of outpatient services, such as disease-specific clinics and centers. None of our models predicts less than a threefold rise in the total number of persons with Alzheimer's disease between 2000 and 2050. Therefore, Alzheimer's care is likely to remain a major public health problem during the coming decades.

Addressing the challenges of transforming laboratory advances into Alzheimer's Disease treatments

This essay addresses the challenges of clinical trials to develop treatments for Alzheimer's Disease (AD). The issues covered are enrolling subjects, defining clinically meaningful endpoints, and making the claim that a drug slows the progression of the disease. The perspective to address these challenges is that dementia research should embrace a biopsychosocial model for drug development. In this model, the patient and caregiver are seen as interrelated subjects of both treatment and research and outcome measures reflect biomarkers of the disease, the functional morbidity of AD and the distress of caregiving.

CD45 isoform alteration in CD4+ T cells as a potential diagnostic marker of Alzheimer's disease

Aging represents the greatest risk for development of Alzheimer's disease (AD), and changes in peripheral immune cell phenotypes have been found to be associated with aging. Using flow cytometry, we measured the relative expression levels of CD45 isoforms, a marker of nai;ve versus memory CD4+ T cell status, on isolated CD4+ T lymphocytes from patients with a clinical diagnosis of probable Alzheimer's disease, normal elderly, cognitively abnormal elderly, and patients with clinically diagnosed other forms of dementia. Data show significantly lower levels of CD45RA, and an increase in the CD45RO/CD45RA ratio, on CD4+ T cells in patients diagnosed with probable Alzheimer's disease (n=46) and in cognitively abnormal individuals (n=37) compared to age-matched normal participants (n=90). Patients diagnosed with other forms of dementia (n=19) did not significantly differ from normal individuals. Both CD45RA and the CD45RO/CD45RA ratio had higher positive and negative predictive values and were more sensitive biomarkers of probable AD than the apolipoprotein E epsilon 4 allele, and had greater predictive ability for probable AD by regression analyses. Additionally, a testing strategy employing apolipoprotein E genotyping and CD45RA or the CD45RO/CD45RA ratio revealed increased sensitivity, positive and negative predictive values, and predictive ability over the apolipoprotein E epsilon 4 allele. These data show altered peripheral immunity in AD patients, and raise the possibility that a testing strategy using CD45 isoform alteration on CD4+ T cells and apolipoprotein E genotype may be clinically valuable for diagnosing probable AD.

Predictors of health and human services use by persons with dementia and their family caregivers

The aim of this study was to identify predictors of the use of health and human services by community residing persons with dementia and their family caregivers. Telephone interviews were conducted with a sample of 608 primary caregivers of community residing persons with dementia who were randomly selected from a state-wide dementia registry. The Anderson Behavioral Model of Health Care Use was used as the analytic framework. Hierarchical ordinary least squares regression models were developed to analyze predictors of health and human services use. Predisposing, enabling, and need variables explained 40.9% of the variance in service use, 29.8% of the variance in health service use, and 38.1% of the variance in the use of human services. Enabling variables explained more variance in the use of health and human services than did need or predisposing variables. In contrast to the health services utilization literature that points to the importance of need variables, the results of this study lend support to findings in the caregiving literature that indicate that enabling variables are at least as important as need variables in predicting the use of community services by family caregivers of persons with dementia.

Survival curve estimation with partial non-random exposure information

The objective of this paper is to estimate survival curves for two different exposure groups when the exposure group is not known for all observations, and the data is subject to left truncation and right censoring. The situation we consider is when the probability that the exposure group is missing may depend on whether the observation is censored or uncensored, in which case the exposure is not missing at random. The problem was motivated by a study of Alzheimer's disease to estimate the distribution of ages at diagnosis for individuals with and without an apolipoprotein E4 allele (the exposure group). Genotyping for this risk factor was incomplete and performed more frequently on the cases of Alzheimer's disease (the uncensored observations) than the censored observations. The survival curves are estimated in discrete time using an EM algorithm. A bootstrapping procedure is proposed that guarantees each bootstrap sample has the same proportion of observations with missing exposure. A simulation is performed to evaluate the bias of the estimators and to investigate design and efficiency issues. The methods are applied to the Alzheimer's disease study.

Prevention of Alzheimer's disease: where we stand

Alzheimer's disease has been recognized as a major public health issue that will grow in prominence as life expectancy increases and as the shape of population demographics shifts toward expansion in the older age ranges with contraction in younger ages. The magnitude of the problem can be expressed in incidence, prevalence economics, and quality of life. Great strides have been made in understanding and treating this disease, but current clinical management is far from satisfactory and progression seems inevitable once the disease is diagnosed. Such forces in any disease encourage intervention strategies to move from treatment to prevention. However, this vision can only be met with reasonable success when pathology is understood and there is evidence that manipulation of that pathology leads to clinical benefit. This is the challenge that lies ahead to achieve the goal of prevention of Alzheimer's disease. This review begins by examining the progress that has been made in this disease. Current efforts to develop prevention strategies are described and possible agents for future evaluation are discussed.

Pharmacotherapy for Alzheimer's disease: progress and prospects

The number of people with Alzheimer's disease has never been greater and is set to increase substantially in the decades ahead as the proportion of the population aged 65 years or more rises sharply. There is, therefore, a substantial and increasing need for effective pharmacotherapy. Increased understanding of disease pathophysiology has led to palliative treatments for both cognitive and non-cognitive changes in behaviour. This, together with the prospect of drugs that slow or perhaps even halt the course of the disease, raises hope that this devastating disorder will soon be more amenable to pharmacotherapy with new drugs that either ameliorate specific symptoms or alter the course of the disease.

Hypertension and hypercholesterolaemia as risk factors for Alzheimer's disease: potential for pharmacological intervention

This paper focuses on hypertension and hypercholesterolaemia as risk factors for Alzheimer's disease and, as such, subjects for prevention. The long-term, prospective, population-based studies regarding the relationship between hypertension or hypercholesterolaemia and Alzheimer's disease, and the clinical studies regarding the association between antihypertensive or lipid-lowering medications and the risk of Alzheimer's disease, are reviewed. These studies provide evidence to suggest that elevated blood pressure and cholesterol levels earlier in life may have an important role in the development and expression of late-life Alzheimer's disease. Based on these data, we propose that proper, early interventions aimed at reducing these cardiovascular risk factors may have an impact on the future incidence and prevalence of Alzheimer's disease.

Evidence for parent of origin effect in late-onset Alzheimer disease

Evidence for a parent of origin effect in Alzheimer disease was obtained from a sample of 148 sibships on which affection status of the parents was sought using family history interviews. The parent study recruited families with two or more affected sibs for late onset AD utilizing rigorous diagnostic criteria. In 74 families, there was evidence of an affected parent, 49 maternal and 25 paternal. Genome scan data were analyzed for the sample as a whole and for the maternal and paternal families separately, using Genehunter-ASM. Seven regions with Z(lr) scores >or=2 were identified, four in maternal families (chr. 10,12,19,20) and three in paternal families (chr. 1,7,13). With the exception of the chromosome 10 finding, analysis by parent of origin greatly increased evidence of linkage in areas showing no linkage in the overall analyses. For example, a chr. 12 region reached a LOD = 2.29 among maternal families whereas the same region showed a LOD = 0.3 when all families were analyzed together. The strongest findings among maternal families (chr. 10 and 12) were followed up with fine mapping that resulted in an increase in maximum LOD scores from 2.7-3.2 on chr. 10, and 2.29-2.42 on chr. 12. These analyses highlight the importance of parent of origin effects in late-onset AD families and identify several genomic regions that may include genes linked to late-onset AD specific to disease transmission from the mother and require further investigation.

Barriers to drug discovery and development for Alzheimer disease

Alzheimer disease (AD) is a neurodegenerative condition leading to progressive, irreversible loss of cognitive and behavioral function. Despite considerable investments in neuroscience research, only four drugs, all cholinesterase inhibitors, have been approved for the symptomatic management of AD in the United States. Although basically safe and modestly effective, these drugs are far from ideal, being neither universally efficacious nor disease modifying. AD exacts a considerable toll in direct medical costs, quality of life, and caregiver burden for persons and society. In addition to the obvious clinical benefit, therapeutic agents for AD and related dementias represent a considerable market opportunity for the pharmaceutical and biotechnology industries. There are currently 8-10 million AD sufferers in the seven major pharmaceutical markets. The market will grow rapidly in coming decades, as the developed world experiences an enormous increase in its elderly population. Given the great need for new therapeutic agents to manage and prevent AD, the Institute for the Study of Aging and the Fidelity Foundation organized a workshop, "Barriers to the Discovery and Development of Drugs for Alzheimer's Disease," to examine ways to expedite drug discovery and development. The identified barriers and potential solutions will be discussed here and in the accompanying articles in more detail.

Clinical trials in AD: are current formats and outcome measures adequate?

Great strides have been made in the measurement of outcomes and treatment efficacy in clinical trials of Alzheimer disease (AD) drugs during the past 25 years. Several sensitive, reliable, and valid clinical outcome measures have been developed. The methodology, trial design, and outcome measures for demonstrating symptomatic benefits of an AD drug are now established. However, a greater challenge lies ahead. Major advances in fundamental knowledge about the pathophysiology of the disease and in animal models have transformed the focus of current efforts to developing and testing therapies that may actually slow disease progression, delay the onset of symptoms, and even ultimately prevent the disease. The long-duration trials that will likely be necessary to demonstrate an effect on disease progression will be costly and difficult. Proof-of-concept trials and subsequent long-term trials could gain power and efficiency from use of biologic markers of underlying disease severity, but currently available biologic markers are not ideal. A major barrier to such trials is their size and cost. One approach to reducing the cost would be to recruit "enriched" samples of subjects who are at greater risk of developing AD during the trial than the general, elderly population. The major effort required to screen and recruit large numbers of subjects for such trials also contributes to the cost. Probably the biggest problem currently is the enormous effort and cost of conducting periodic clinical evaluations to determine if subjects have declined or developed dementia. Research to develop more efficient assessment methods is clearly needed. Data acquisition over the Internet is potentially efficient and attractive and may become practical as Internet accessibility increases.

Depression in Alzheimer's disease: overview and treatment

Psychiatric disturbances affect as many as 90% of patients with Alzheimer's disease (AD) and are a major focus of treatment. Depression is one of the most frequent psychiatric complications of AD, affecting as many as 50% of patients. In this context, depression is a significant public health problem that has a series of serious adverse consequences for patients and their caregivers. There has been little research into the course or treatment of depression associated with AD. This is in part due to the absence of validated operational criteria for defining depression in AD. Recently, the National Institute of Mental Health (NIMH) convened an expert consensus panel to develop draft criteria for depression of Alzheimer's disease (NIMH-dAD) and to establish research priorities in this area. This article provides an overview of recent knowledge with regard to depression in AD with a special emphasis on its treatment. We conclude with recommendations for further research in this area.

Reminiscence group activities and discourse interaction in Alzheimer's disease

Reminiscence is an enriching and complex experience having many purposes and functions when used with patients with Alzheimer's disease (AD). Discourse is a component of language that has been shown to decline in patients with AD (Mentis, Briggs-Whittaker, & Gramigna, 1995). This article represents one of the first studies to examine the effects of reminiscence group (RG) activities on discourse interactions in patients with AD. This article specifically addresses the AD population within a RG setting. Observations suggested that objective ratings of conversational discourse would be better (less impaired) in patients with AD when obtained in relatively unstructured environments (e.g., during RG activity) as compared to ratings obtained in conversational environments imposing more structure (e.g., a session in which language function was being evaluated). Comparisons made of conversational and narrative discourse skills observed during different testing environments in patients with AD revealed predicted outcomes. That is, discourse elicited in an environment that was less structured yielded qualitatively better discourse patterns, particularly related to selecting and maintaining a topic, requesting additional information about a topic, changing a topic during conversation, and turn-taking. Results are discussed in terms of their relevance to gerontological nurses managing patients with AD.

Discourse-derived perspectives: differentiating among spouses' experiences of caregiving

A method of constant comparative analysis was used to code open-ended interviews with 132 spouse caregivers regarding their experiences in caregiving. Results of this analysis yielded 69 qualitative code categories. We used these categories to compare the caregivers on several groupings that the literature has identified as providing meaningful ways to differentiate among caregivers. We used the qualitative responses to compare the caregivers by caregiver gender care-recipient dementia severity, and duration of caregiving. Results partly confirmed previous findings that wife caregivers are more distressed than husbands, but the results also indicated these caregivers were more similar than dissimilar The other analyses likewise indicated greater similarities than dissimilarities in the caregiving experience. We next continued the analysis and, using the coding categories as a springboard, identified four distinct patterns for construction of the meaning of the caregiving experience in the caregivers' discourse. These discourse-derived framing categories, applicable in about three-quarters of the caregivers, offered other ways to distinguish among caregivers. Further analysis of these robust groupings' showed important differences among the groups. These framing categories suggest ways to differentiate among caregivers, based on their perception of their role in the caregiving situation, ways that might point the way to intervention strategies for each of the groupings.

Dementia epidemiology

Determining the incidence and prevalence of dementia is an inexact science. Dementia is difficult to define and detect in the population. Even with the difficulties of determining prevalence and incidence, it is clear that dementia causes a substantial burden on our society. Problems with diagnostic inaccuracy and insidious disease onset influence our ability to observe risk factor associations; factors related to survival may be mistaken for risk/protective factors. Current studies suggest that factors influencing brain development or cognitive reserve may delay the onset of AD, perhaps through a protective mechanism or a delay in diagnosis caused by improved performance on cognitive tests. The recent identification of genes that cause dementia suggests that these genes or their biochemical pathways may be involved in the pathogenesis of nonfamilial cases. The contribution of genes that cause disease in and of themselves may be smaller than that of genes that act to metabolize or potentiate environmental exposures. The interaction between gene and environment should be increasingly well studied in the future. Epidemiology must take advantage of these molecular advances. The tasks of public health and epidemiology should still involve prevention, the nonrandom occurrence of disease, and its environmental context in addition to heredity. The tools to address these tasks should continue to be refined.

Predictors of nursing home admission and/or death in incident Alzheimer's disease and other dementia cases compared to controls: a population-based study

This research elucidates the risk of institutional care and/or death of patients with Alzheimer's disease (AD) or other dementia (OD) compared with noncases. Community dwelling incident cases of AD (n = 240) or OD (n = 208) and age-matched noncases (n = 363) living in an enumerated population were included. The adjusted hazard ratio (HR) of being admitted to a nursing home compared with controls was 5.44 (95% confidence interval, CI: 3.68,8.05) for AD cases and 5.08 (95% CI: 3.38, 7.63) for OD cases. The adjusted RR of death compared to controls was 1.90 (95% CI: 1.36, 2.65) for AD cases and 2.27 (95% CI: 1.62, 3.18) for OD cases. This is the only population-based study in the U.S. documenting that AD/OD increases the risk of death independent of comorbid conditions. AD/OD patients have more comorbidities and are at greater risk of entering a nursing home than to die during the follow-up, compared with those without these diagnoses.

Memories in the making: outcome-based evaluation of an art program for individuals with dementing illnesses

The author presents the results of a pilot project, an outcomes-based evaluation of Memories in the Making: An art program for individuals with dementing illnesses. Sponsored by the Greater Cincinnati Chapter of the Alzheimer's Association and implemented at adult day and nursing home sites, participants in the weekly art program use paints to express themselves by creating colorful visual images on paper or fabric. The individuals experienced pleasurable, sustained activity while engaged in making art. Utilizing M.P. Lawton's conceptualization of psychological well-being as a framework, chapter staff developed an observational instrument, which measured objective and subjective indicators of the affect state and self-esteem of 41 participants in the art program. Overall, preliminary data suggests that participation in the weekly sessions contributed to the individuals' sense of well-being. However, more rigorous study is warranted using comparison groups to determine if indeed an enhanced sense of well-being can be attributed with certainty to the intervention of the Memories in the Making art program.