Beta amyloid PET scans for dementia diagnoses: Practice and research implications from CARE-IDEAS.

Beta amyloid PET scans are a minimally invasive biomarker that may inform Alzheimer's disease (AD) diagnosis. The Caregiver's Reactions and Experience (CARE) study, an IDEAS supplement, aimed to understand experiences of PET scan recipients and their care partners regarding motivations for scans, reporting and interpreting results, and impact of results. Patients with mild cognitive impairment or dementia who agreed to join the CARE-IDEAS study and their care partners participated in a baseline survey and follow-up survey approximately 18 months later, supplemented by in-depth qualitative interviews with subsets of participants. Patients who received scans and volunteered for follow-up research were more likely to be male, better educated, and have higher income than the general population. Survey information was merged with Medicare data. This article integrates findings from several CARE-IDEAS publications and provides implications for practice and research. Although most participants accurately reported scan results, they were often confused about their meaning for prognosis. Some participants reported distress with results, but there were no significant changes in measured depression, burden, or economic strain over time. Many respondents desired more information about prognosis and supportive resources. Scan results were not differentially associated with changes in service use over time. Findings suggest a need for carefully designed and tested tools for clinicians to discuss risks and benefits of scans and their results, and resources to support patients and care partners in subsequent planning. Learning of scan results provides a point-of-contact that should be leveraged to facilitate shared decision-making and person-centered longitudinal AD care.

Elevated Amyloid-ß PET Scan and Cognitive and Functional Decline in Mild Cognitive Impairment and Dementia of Uncertain Etiology.

BACKGROUND: Elevated amyloid-ß (Aß) on positron emission tomography (PET) scan is used to aid diagnosis of Alzheimer's disease (AD), but many prior studies have focused on patients with a typical AD phenotype such as amnestic mild cognitive impairment (MCI). Little is known about whether elevated Aß on PET scan predicts rate of cognitive and functional decline among those with MCI or dementia that is clinically less typical of early AD, thus leading to etiologic uncertainty. OBJECTIVE: We aimed to investigate whether elevated Aß on PET scan predicts cognitive and functional decline over an 18-month period in those with MCI or dementia of uncertain etiology. METHODS: In 1,028 individuals with MCI or dementia of uncertain etiology, we evaluated the association between elevated Aß on PET scan and change on a telephone cognitive status measure administered to the participant and change in everyday function as reported by their care partner. RESULTS: Individuals with either MCI or dementia and elevated Aß (66.6% of the sample) showed greater cognitive decline compared to those without elevated Aß on PET scan, whose cognition was relatively stable over 18 months. Those with either MCI or dementia and elevated Aß were also reported to have greater functional decline compared to those without elevated Aß, even though the latter group showed significant care partner-reported functional decline over time. CONCLUSIONS: Elevated Aß on PET scan can be helpful in predicting rates of both cognitive and functional decline, even among cognitively impaired individuals with atypical presentations of AD.

Prevalence and incidence of depressive symptoms and diagnosis of depression as associated with elevated amyloid among Medicare beneficiaries with cognitive impairment.

BACKGROUND: Depression and cognitive impairment commonly co-occur, and it has been hypothesized that the two share pathological processes. Our objective for this study was to determine the relationship between elevated ß-amyloid level and the prevalence and incidence of depressive symptoms and diagnosed depression over two years among fee-for-service Medicare beneficiaries with cognitive impairment. METHODS: We utilized data from the CARE-IDEAS cohort study (N = 2078) including two measures of depressive symptoms (PHQ-2) and administrative claims data to identify pre-scan and incident depression diagnosis in subsample of fee-for-service Medicare beneficiaries (N = 1443). We used descriptive statistics and Poisson regression models with robust covariance. RESULTS: Beneficiaries whose scan results indicated not-elevated ß-amyloid were significantly more likely to have been diagnosed with depression pre-scan (46.4 % vs. 33.1 %). There was no significant association between elevated amyloid and the incidence of depressive symptoms or diagnosed depression. LIMITATIONS: The sample was limited to Medicare beneficiaries with cognitive impairment. Race/ethnic composition and education levels were not representative of the general population and there was substantial loss to follow-up. Mixed depressive / anxious episodes were captured as diagnoses of depression, potentially overestimating depression in this population. CONCLUSIONS: There was a high prevalence and incidence of diagnosed depression in this cohort of Medicare beneficiaries, but the incidence of depressive symptoms and diagnosed depression was not associated with elevated ß-amyloid.

Reactions to Amyloid PET Scan Results and Levels of Anxious and Depressive Symptoms: CARE IDEAS Study.

BACKGROUND AND OBJECTIVES: Few studies have examined care partners' reactions to their loved ones receiving amyloid-ß positron emission tomography (PET) scan results, which can be indicative of Alzheimer's disease. We explored care partners' reactions qualitatively, and checked the association of scan results and diagnostic category (dementia vs mild cognitive impairment [MCI]) with care partner anxious and depressive symptoms through quantitative analysis. RESEARCH DESIGN AND METHODS: Using data from 1,761 care partners in the Caregivers' Reactions and Experience, a supplemental study of the Imaging Dementia Evidence for Amyloid Scanning study, we applied an exploratory sequential mixed-methods design and examined the reactions of 196 care partners to receiving amyloid PET scan results through open-ended interview questions. Based on the qualitative content analysis, we hypothesized there would be an association of care partners' depressive (Patient Health Questionnaire-2) and anxious (6-item State-Trait Anxiety Inventory) symptoms with scan results and diagnostic category which we then tested with logistic regression models. RESULTS: Content analysis of open-ended responses suggests that when scan results follow the care partner's expectations, for example, elevated amyloid in persons with dementia, care partners report relief and gratitude for the information, rather than distress. Adjusted logistic regression models of survey responses support this finding, with significantly higher odds of anxiety, but not depressive symptoms, among care partners of persons with MCI versus dementia and elevated amyloid. DISCUSSION AND IMPLICATIONS: Care partners of persons with MCI reported distress and had higher odds of anxiety after receiving elevated amyloid PET scan results than care partners of persons with dementia. This has the potential to inform clinical practice through recommendations for mental health screening and referrals.

Advance directives among cognitively impaired persons who had an amyloid PET scan and their care partners: a mixed-methods study.

BACKGROUND: Little research exists on the role of ß-amyloid PET scans as part of Alzheimer's diagnostic tests and documentation of end-of-life preferences for persons with cognitive impairment. The study objectives were to examine the association of amyloid PET scan results (elevated vs. not elevated amyloid levels) and diagnostic category (mild cognitive impairment vs. dementia) with the likelihood of having an advance directive (reported a median of 4.5 months post-scan); to explore perceptions of PET scan results and their influence on planning for the future among persons with cognitive impairment and their care partners. METHODS: Sequential, explanatory mixed-methods design using data from dyads in the CARE-IDEAS study: advance directives as a factor of diagnostic category and scan result using multivariable logistic regression models; thematic analysis of semi-structured interviews with persons with cognitive impairment and care partners to explore how scan results influenced documentation of future healthcare preferences. Participants included 1784 persons with cognitive impairment and care partners from the CARE-IDEAS study, and a subsample of 100 semi-structured telephone interviews. RESULTS: 81.6% of dyads reported an advance directive. Non-Hispanic, White participants had higher rates of advance directives. There was no significant association between having an advance directive and scan results. Qualitative analysis provided insight into perceived urgency to have advance directives, evolving healthcare preferences, and the context of completing advance directives. CONCLUSIONS: Although amyloid PET scans prompted persons with cognitive impairment and care partners to consider progressive cognitive impairment as part of evolving healthcare preferences, we found substantial variability in the perceived urgency of documentation.

Amyloid-ß PET Scan Results Disclosure and Care-Partner Emotional Well-Being Over Time.

BACKGROUND: Diagnostic tests, such as amyloid-ß positron emission tomography (PET) scans, can increase appropriate therapeutic management for the underlying causes of cognitive decline. To evaluate the full utility of this diagnostic tool, information is needed on whether results from amyloid-ß PET scans influence care-partner outcomes. OBJECTIVE: This study examines the extent to which previous disclosure of elevated amyloid (suggestive of Alzheimer's disease (AD) etiology) versus not-elevated amyloid (not suggestive of AD etiology) is associated with changes in care-partner wellbeing. METHODS: The study used data derived from a national longitudinal survey of Medicare beneficiaries (n = 921) with mild cognitive impairment (MCI) or dementia and their care-partners. Care-partner wellbeing outcomes included depressive symptoms (PHQ-8), subjective burden (4-item Zarit burden score), and a 3-item measure of loneliness. Change was measured between 4 (Time 1) and 18 (Time 2) months after receiving the scan results. Adjusted linear regression models regressed change (Time 2-Time 1) in each outcome on scan result. RESULTS: Care-partners were primarily white, non-Hispanic, college-educated, and married to the care recipient. Elevated amyloid was not associated with statistically significant Time 1 differences in outcomes or with statistically significant changes in depressive symptoms 0.22 (-0.18, 0.61), subjective burden 0.36 (-0.01, 0.73), or loneliness 0.15 (-0.01, 0.32) for care-partners from one time point to another. CONCLUSION: Given advances in AD biomarker testing, future research in more diverse samples is needed to understand the influence of scan results on care-partner wellbeing across populations.