The incremental direct costs associated with behavioral symptoms in AD

OBJECTIVE

To determine the incremental costs associated with behavioral symptoms in patients with AD.

METHODS

A total of 128 patients with probable AD were enrolled into this study. Cognitive function and extrapyramidal features were assessed in patients with AD. Caregivers were interviewed to determine use of health care services, receipt of unpaid care, severity of behavioral symptoms (Neuropsychiatric Inventory [NPI]), and comorbid medical conditions in patients with AD. Healthcare utilization data were multiplied by unit costs to estimate direct formal costs. Unpaid caregiving hours were multiplied by an hourly wage to estimate direct informal costs. The annual incremental direct costs of additional behavioral symptoms were estimated with multiple regression equations.

RESULTS

Annual, direct costs were significantly higher in patients with AD at or above the median score on the NPI (high NPI group), after adjusting for group differences in severity of cognitive impairment and comorbid conditions. Patients in the high NPI group had formal costs between US$3,162 and US$5,919 higher than the low NPI group and total direct costs between US$10,670 and US$16,141 higher, depending on the severity of cognitive impairments. Models for the entire sample estimated that a one-point increase in the NPI score would result in an annual increase of between US$247 and US$409 in total direct costs, depending on the value of unpaid caregiving.

CONCLUSIONS

Behavioral symptoms in patients with AD significantly increase direct costs of care.

Comparison of healthcare utilization and direct costs in three degenerative dementias

The authors conducted a survey of healthcare utilization in three dementia syndromes to determine whether type of dementia influenced utilization or resulting direct costs. Patients with Alzheimer disease (n=131), dementia with parkinsonism (n=85), and Huntington disease (n=51) were identified from a registry and enrolled. Caregivers completed the mailed survey, and direct costs were estimated. The presence of dementia with parkinsonism resulted in significantly greater utilization of long-term care services and higher total direct costs. In all three groups, long-term care costs accounted for the majority of direct costs. Unique patterns of utilization and costs are seen in specific neurodegenerative dementias.

The costs of caring: medical costs of Alzheimer's disease and the managed care environment

This review summarizes the medical costs associated with Alzheimer's disease (AD) and related dementias, as well as the payers responsible for these medical costs in the US health care system. It is clear from this review that AD and related dementias are associated with substantial medical costs. The payers responsible for a majority of these costs are families of patients with AD and the US government through the Medicare and Medicaid programs. In an attempt to control expenditures, Medicare and Medicaid have turned to managed care principles and managed care organizations. The increase in "managed" dementia care gives rise to several potential problems for patients with AD, along with many opportunities for systematic improvement in the quality of dementia care. Evidence-based disease management programs provide the greatest opportunities for improving managed dementia care but will require the development of dementia-specific quality of care measures to evaluate and continually improve them.

Cost-utility of three approaches to the diagnosis of sleep apnea: polysomnography, home testing, and empirical therapy

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) is usually diagnosed with overnight polysomnography in a sleep laboratory. Home sleep studies can be performed at lower cost, but results are somewhat less reliable. Bedside diagnosis of OSAS without any testing has also been discussed.

OBJECTIVE

To model the costs and utility of laboratory polysomnography, home study, and no testing during the 5 years after initial evaluation for OSAS.

DESIGN

Cost-utility analysis.

DATA SOURCES

Published data.

TARGET POPULATION

Hypothetical cohort of persons suspected of having OSAS.

TIME HORIZON

The 5 years after initial evaluation for OSAS.

PERSPECTIVE

Societal.

INTERVENTION

Nasal continuous positive airway pressure when OSAS was diagnosed.

MEASUREMENTS

Quality of life, survival and charges (as proxies for costs) for each diagnostic method.

RESULTS OF BASE-CASE ANALYSIS

Under almost all modeled conditions, polysomnography provided maximal quality-adjusted life-years in the 5 years after the initial diagnostic evaluation. The incremental charges for polysomnography over home study or no testing were about $13,400 and $9200, respectively, per quality-adjusted life-year gained during this period.

RESULTS OF SENSITIVITY ANALYSIS

Results were sensitive to the utility of treatment in the absence of OSAS.

CONCLUSIONS

The cost-utility of polysomnography instead of home study or no testing in the diagnosis of OSAS compares favorably with that of other procedures for which society judges the added utility per dollar spent to be worthwhile. More precise determination of certain key variables in this model should be a goal of future research.

Cognitive, behavioral, and motor effects of the NMDA antagonist ketamine in Huntington's disease

BACKGROUND

Excitotoxicity may contribute to neuronal degeneration in Huntington's disease (HD). N-methyl-D-aspartate (NMDA) receptor antagonists can prevent neuronal degeneration caused by excitotoxicity, but their effects in HD patients are not known.

METHODS

We investigated the acute cognitive, behavioral, and motor effects of the NMDA-receptor antagonist ketamine in HD patients. Double-blind infusions of 0.10, 0.40, and 0.60 mg/kg/hr ketamine were given to 10 HD patients on one test day and compared with placebo infusions on a second, identical testing day. Linear mixed-effects models and randomization tests were used to identify whether, and at which dose, a significant change from baseline occurred in outcome variables.

RESULTS

We demonstrated that ketamine is well tolerated at low and intermediate subanesthetic doses. Intermediate ketamine doses produced specific decline in memory and verbal fluency. Higher subanesthetic doses caused a significant increase in psychiatric symptoms and impairment of eye movements.

CONCLUSIONS

These results describe the spectrum of clinical effects produced by increasing NMDA receptor blockade in HD patients. The clinical effects appearing with higher levels of NMDA receptor blockade can identify the range of doses used in clinical trials of NMDA receptor antagonists.

Apolipoprotein E and Alzheimer's disease: strength of association is related to age at onset

Apolipoprotein E (apoE) epsilon 4 allele frequency among Alzheimer's disease (AD) patients is increased compared to control subjects and is influenced by the presence of other genetic factors and age at symptom onset. We examined the relationship between age at AD symptom onset and apoE by comparing the apoE epsilon 4 allele frequency of normal, elderly control subjects (n = 107) to that in AD patients (n = 123), divided into four age-at-onset periods. Additionally, the distribution of symptom onset ages of AD patients with and without apoE epsilon 4 alleles was determined. We observed increased apoE epsilon 4 allele frequencies between the AD onset ages of 55 and 75 years, but not at the extremes of onset ages (i.e. onset between 45 and 54 years of age and after age 75). Our data suggests that having an apoE epsilon 4 allele increases the likelihood that AD patients will develop symptoms in the middle range of onset ages. At the extremes of AD onset ages, non-apoE factors, including other genetic factors and age, are more important determinants of risk of developing AD.

Novel amyloid precursor protein gene mutation (codon 665Asp) in a patient with late-onset Alzheimer's disease

Amyloid plaques in Alzheimer's disease contain beta-amyloid, encoded by portions of exons 16 and 17 of the amyloid precursor protein. The specific association of rare amyloid precursor protein mutations with some kindreds with early-onset familial Alzheimer's disease suggests that specific abnormalities in amyloid precursor protein may contribute to the pathogenesis of Alzheimer's disease. Until now, there has been no evidence suggesting that amyloid precursor protein mutations could be involved in late-onset or sporadic Alzheimer's disease. We used reverse transcription-polymerase chain reaction, denaturing gradient gel electrophoresis, and direct DNA sequencing to analyze amyloid precursor protein exons 16 and 17 from postmortem cerebellar samples from patients with histologically confirmed Alzheimer's disease and control subjects. We found a novel point mutation, substitution of cytosine for guanine, at nucleotide 2119 (amyloid precursor protein 770 messenger RNA transcript) in a patient with late-onset Alzheimer's disease. This substitution deletes a BglII site and substitutes aspartate for glutamine at codon 665. Denaturing gradient gel electrophoresis analysis showed that this mutation was absent in 40 control subjects and 127 dementia patients. Whether this mutation is a rare but normal variant or contributes to the development of Alzheimer's disease is not known. The BglII restriction fragment length polymorphism enables investigators to determine the frequency of this polymorphism in normal subjects and Alzheimer's disease patients.

Neuroimaging of epilepsy, movement disorders, and degenerative diseases

Neuroimaging has improved the understanding, diagnosis, and management of several neurologic diseases and syndromes. Recent advances in the neuroimaging of epilepsy, movement disorders, and degenerative diseases of the nervous system are reviewed. Current research confirms that structural and functional neuroimages each provide unique, clinically useful information in these disorders. Quantification of images improves their diagnostic sensitivity and specificity. Presymptomatic or early neurochemical changes have been identified and followed longitudinally in several neurodegenerative diseases, providing a method for monitoring response to therapeutic intervention and pathophysiologic hypothesis testing. Functional activation studies and receptor-specific radioligands continue to advance our understanding of these disorders. Future methods will take increasing advantage of both the ability to measure neuropharmacological and neurochemical changes in vivo, and the ability to combine images and information obtained with distinct structural and functional neuroimaging modalities.