Baseline levels and longitudinal rates of change in plasma Aβ42/40 among self-identified Black/African American and White individuals

Objective

The use of blood-based biomarkers of Alzheimer disease (AD) may facilitate access to biomarker testing of groups that have been historically under-represented in research. We evaluated whether plasma Aβ42/40 has similar or different baseline levels and longitudinal rates of change in participants racialized as Black or White.

Methods

The Study of Race to Understand Alzheimer Biomarkers (SORTOUT-AB) is a multi-center longitudinal study to evaluate for potential differences in AD biomarkers between individuals racialized as Black or White. Plasma samples collected at three AD Research Centers (Washington University, University of Pennsylvania, and University of Alabama-Birmingham) underwent analysis with C2N Diagnostics' PrecivityAD™ blood test for Aβ42 and Aβ40. General linear mixed effects models were used to estimate the baseline levels and rates of longitudinal change for plasma Aβ measures in both racial groups. Analyses also examined whether dementia status, age, sex, education, APOE ε4 carrier status, medical comorbidities, or fasting status modified potential racial differences.

Results

Of the 324 Black and 1,547 White participants, there were 158 Black and 759 White participants with plasma Aβ measures from at least two longitudinal samples over a mean interval of 6.62 years. At baseline, the group of Black participants had lower levels of plasma Aβ40 but similar levels of plasma Aβ42 as compared to the group of White participants. As a result, baseline plasma Aβ42/40 levels were higher in the Black group than the White group, consistent with the Black group having lower levels of amyloid pathology. Racial differences in plasma Aβ42/40 were not modified by age, sex, education, APOE ε4 carrier status, medical conditions (hypertension and diabetes), or fasting status. Despite differences in baseline levels, the Black and White groups had a similar longitudinal rate of change in plasma Aβ42/40.

Interpretation

Black individuals participating in AD research studies had a higher mean level of plasma Aβ42/40, consistent with a lower level of amyloid pathology, which, if confirmed, may imply a lower proportion of Black individuals being eligible for AD clinical trials in which the presence of amyloid is a prerequisite. However, there was no significant racial difference in the rate of change in plasma Aβ42/40, suggesting that amyloid pathology accumulates similarly across racialized groups.

Social Determinants of Alzheimer’s Disease and Related Dementias: Racial and Regional Variations

To examine whether racial and regional social determinants of health disparities exist for older adults with Alzheimer’s disease and related dementias (ADRD). We identified 115,879 African American (AA) and White older adults with ADRD (10% from the Deep South) from administrative claims data for a 5% random sample of Medicare beneficiaries (2013-2015). We examined racial and regional differences across sociodemographic characteristics, county-level linked poverty indicators, medical resource availability categories, insurances quality indicators. Social context differences were found between regions including Deep South older adults with ADRD having higher economic impoverishment and lower access rates to specialty medical care services. Older Deep South AA had higher Medicare/Medicaid eligibility rates and less medical access. Significant socioeconomic disparities exist between Deep South and other US regions across several social determinant factors in older adults with ADRD. Social context differences were especially prominent for older Deep South AA with ADRD.

The Challenge of Identifying Representative Samples in Research Involving Minority Participants

Determining participants' demographics, cognition, and functional performance by race is crucial to understanding disparities in clinical research on Alzheimer’s disease. We compared demographic and performance variables between Black/African American (B/AA; N=30; 41%) and White participants (N=43, 59%) in the UAB Alzheimer's Disease Center. Among 73 participants, 38 (52%) were women, mean age was 65.7 (SD 9.47), and mean education was 16 (2.31) years. Significant differences in gender proportions across race groups were observed. B/AA women represented 70 % of their race group, white women represented 39.5 %. There were no statistically significant differences in age, education, cognitive or functional severity, reasons to participate in research, referral source, objective measures of cognition, or informant-rated daily function by race group. In conclusion, despite 50% oversampling of B/AA participants compared to the State population, no differences in cognitive and functional performance at the time of enrollment were associated with race.

Health Care Utilization in Diverse Older Adults in the Deep South and the Rest of the United States

We examined racial/ethnic (R/E) differences in health care utilization among older adults with Alzheimer’s disease and related dementia (ADRD) from US Deep South [DS] and non-DS, and individual or context-level factors that affect this utilization. Data were 2013-2015 claims for Medicare beneficiaries with ADRD; county-level data were used to define context-level covariates; adjusted analyses were conducted separately for DS and non-DS. Across R/E groups, 33%-43% in DS, 43%-50% in non-DS used ADRD specialists; 47%-55% in DS, 41%-48% in non-DS used ADRD drugs; 42.9%-53.4% in DS, 42%-51.8% in non-DS had hospitalizations in a one-year follow-up. R/E differences were not significant, with few exceptions. Comorbidities, poverty, and medical resources availability were associated with specialist use and hospitalizations; comorbidities and specialist use were associated with drug use. In non-DS only, other individual, context-level covariates were associated with health care outcomes. Research should further examine determinants of health care utilization in these populations.

Dementia Caregiver Surrogate Decision Making Self-Efficacy:Distress, and Quality of Life

We assessed the relationship between caregiver self-efficacy and caregivers’ ratings of care recipient’s health-related quality of life, the severity of neuropsychiatric symptoms, and associated caregiver distress for persons with Alzheimer’s dementia (AD). Methods: The 31-item DEMQOL-Proxy, Neuropsychiatric Inventory (NPI-Q), and the Self-Efficacy for Surrogate Decision-Making scale (SDM-SES) were collected from 26 family caregivers of people with AD expressing care resistant behaviors. We used Spearman correlations to assess relationships between SDM-SES, NPI-Q severity, and NPI-distress and DEMQOL-proxy. Among enrolled caregivers, 14 (54%) were women; mean age was 64.5 years, and 24 (92%) were college-educated. Their care recipients were 61% women, 77 % white, with a mean age of 76 years, and mostly college-educated (88%). Mean scores were DEMQOL-Proxy 91.27 (+/- 14.16), SDM-SES 16.38 (+/- 2.74), NPI-Q Severity score 14.23 (+/- 6.04), and NPI-distress 17.42 (+/-6.90). There were moderate correlations between DEMQOL-Proxy and SDM-SES (r=0.54), NPI severity (r= -0.42) and NPI-distress (r= -0.49). Secondary analysis showed a moderate correlation between SDM-SES and NPI-distress (r= -0.40). We identified associations between caregiver self-efficacy, quality of life, and caregiver distress. A higher baseline SDM-SES was associated with greater health-related quality of life for the care recipient. Lower self-efficacy scores were related to more caregiver distress related to neuropsychiatric symptoms. Higher NPI severity and caregiver distress were associated with lower quality of life for the care recipient. Interventions targeting self-efficacy may promote improved QOL and decrease caregiver distress in AD dyads.

Perspectives of Family Caregivers Confronted With Care-Resistant Behavior From Persons With Dementia

Problem: Care-resistant behavior is often bundled with other behavioral symptoms of dementia, but it is a unique behavior requiring targeted interventions. Purpose: To describe the experiences of caregivers receiving online coaching to manage care-resistant behaviors exhibited by persons with dementia. Design: Qualitative. Sample & Procedure: 20 caregivers (12 female, 8 male) were recruited from Memory Disorders and Geriatrics clinics to participate in 6 weeks of online coaching sessions delivered by a doctorally prepared nurse practitioner. Coaching sessions were recorded and transcribed. NVivo12 software was used to manage the thematic analyses. Results: Caregivers followed a general trajectory. They initially reported feelings of anger, frustration, and guilt. They believed that the person with dementia was purposefully “being stubborn and mean.” As the coaching sessions progressed, these negative emotions and the attributions of intent altered. By the conclusion of the six weeks, caregivers expressed feelings of success and ingenuity in applying coaching strategies. Conclusion: Online coaching is an effective way to individualize strategies that enable the caregiver to manage and reduce care-resistant behavior. Implications: The use of a doctorally-prepared nurse practitioner to deliver coaching, while effective, is not sustainable. Next steps include developing a coaching training program that could be embedded into existing community resources for community-dwelling caregivers. Limitations: Participants were limited to referrals from two clinics in the same institution.

FEASIBILITY OF ONLINE SYNCHRONOUS CAREGIVER DEMENTIA COACHING FOR REJECTION-OF-CARE BEHAVIORS

Problem: Two-thirds of family caregivers of persons living with dementia have encountered rejection-of-care behavior, usually during assistance with activities of daily living. Purpose: To describe the feasibility of an online videoconferencing platform to help caregivers prevent and reduce ROC behavior. Design: Quasi-experimental. Sample: Twenty-six family caregivers: 54% female, 77% white, 62% spouses (31% wives, 31% husbands), mean age 65 years, and college-educated (92%). Their care recipients were 61% female, 77% white, mean age of 76 years, and college-educated (88%). Procedure: Family caregivers who endorsed problematic ROC behaviors in their care recipients participated in six online, individual, synchronous, sequential, and weekly 1-hour coaching sessions. We measured general burden (Zarit Burden Inventory) and the frequency, severity, and associated distress of responsive behaviors (Neuropsychiatric Inventory Questionnaire). Data collection intervals were before coaching (baseline), immediately after the final session (Time 1), and six weeks (Time 2) and 12 weeks (Time 3) after the final session, respectively. Results: Caregivers reported less overall distress scores at Time 2 compared to baseline: 13.58 (SD 6.44) versus 17.42 (SD 6.90), t=2.56, p=0.017). Distress scores returned to baseline by Time 3. Caregivers reported less severe ROC behavior at Time 2 which was not statistically significant. Burden remained unchanged throughout the 24 weeks. Conclusion: Online caregiver coaching that targets ROC behavior is feasible. Qualitative review of the encounters suggests that a longer period of intervention and an outcome measure more sensitive to ROC effects on activities of daily living may be needed in future studies.

The Potential of Information Technology to Navigate Caregiving Systems: Perspectives from Dementia Caregivers

Technologies designed to support caregivers of adults with Alzheimer's disease and related dementias (AD/RD) have been developing at an increasingly rapid pace. However, little remains known about caregivers' perspectives on how technologies can and should help them navigate larger service systems they interact with to engage in caregiving. This study involved in-depth interviews and a beta test of an AD/RD caregiver app to learn more about how they currently use technologies and how potential technological features and functions can best meet their needs. Thematic findings suggest a conceptual model for designing AD/RD caregiver technologies. The findings suggest that eHealth and individual technologies may not fully meet the needs of caregivers as they navigate the larger systems within which they provide care. Findings highlight the need to develop technologies for caregivers that are effective, easy to use, and more widely disseminated - especially for caregivers from disadvantaged backgrounds.

High-dose donepezil (23 mg/day) for the treatment of moderate and severe Alzheimer's disease: drug profile and clinical guidelines

To provide healthcare professionals with a comprehensive assessment of donepezil 23 mg and its role in treating Alzheimer's disease (AD), the Donepezil 23 mg Expert Working Group (EWG) convened in June 2011 to critically evaluate the clinical trial database for this higher dose formulation and the members' clinical experience with its use. Discussions were based on a large, 6-month, phase 3 clinical trial in patients with moderate to severe AD that compared continuing donepezil 10 mg/day versus switching to 23 mg/day. In this trial, donepezil 23 mg/day demonstrated significantly greater cognitive benefits (mean change in Severe Impairment Battery score, 2.11 points; P < 0.001). Prespecified analyses showed that benefits were significant irrespective of concomitant memantine use. The EWG considered integrating these new data into clinical practice approaches. Dementia severity, tolerability of the 10 mg dose, and need for additional therapy were key selection criteria, as was monitoring of gastrointestinal side effects, as consideration of titration strategies is an important aspect of implementation. The EWG concluded that donepezil 23 mg is an efficacious therapy for moderate to severe AD, with or without concomitant memantine, extending the treatment opportunities available to manage moderate to severe AD dementia. EWG guidelines offer assistance to clinicians in choosing and implementing treatment options.

Subgroup analysis of US and non-US patients in a global study of high-dose donepezil (23 mg) in moderate and severe Alzheimer's disease

To better understand responses in the large number of US-based patients included in a global trial of donepezil 23 mg/d versus 10 mg/d for moderate-to-severe Alzheimer's disease (AD), post hoc exploratory analyses were performed to assess the efficacy and safety in US and non-US (rest of the world [RoW]) patient subgroups. In both subgroups, donepezil 23 mg/d was associated with significantly greater cognitive benefits than donepezil 10 mg/d. Significant global function benefits of donepezil 23 mg/d over 10 mg/d were also observed in the US subgroup only. Compared with RoW patients, US patients had relatively more severe AD, had been treated with donepezil 10 mg/d for longer periods prior to the start of the study, and a higher proportion took concomitant memantine. In both subgroups, donepezil had acceptable tolerability; overall incidence of treatment-emergent adverse events was higher in patients receiving donepezil 23 mg/d compared with donepezil 10 mg/d.

Development of cognitive instruments for use in clinical trials of antidementia drugs: additions to the Alzheimer's Disease Assessment Scale that broaden its scope. The Alzheimer's Disease Cooperative Study

The cognitive assessment protocol of the Alzheimer's Disease Cooperative Study (ADCS) was designed to evaluate the reliability and validity of cognitive assessment measures that might be valuable additions to the Alzheimer's Disease Assessment Scale (ADAS) or other concise batteries used in antidementia drug trials. As part of an overall ADCS protocol to develop new instruments to be used in trials of treatments for Alzheimer's disease (AD), patients with mild to moderate AD and cognitively normal elderly were administered a battery of five tests at least three times over 1 year. The tests included word list learning with delayed free recall, a recognition memory test for faces, a series of letter and digit cancellation tests to measure concentration, tests of praxis, and a series of maze completion tasks designed to assess planning and executive function. A version of the digit cancellation task was reliable and sensitive to a broad range of dementia severity so that it could provide a useful addition to the present version of the ADAS. Performance on the word learning task with delayed recall and a subset of the mazes task were impaired even in mild AD, so these tasks may be useful in trials involving mild or at-risk subjects. Performances on the facial recognition task and on the praxis tasks were not related to dementia severity, so these tasks would not be useful to evaluate treatments. Therefore, the major outcome of this investigation was the identification of some potential additions to the present ADAS that extend both the cognitive domains and the range of symptom severity covered.

Nonoptic aphasia: aphasia with preserved confrontation naming in Alzheimer's disease

Patients with Alzheimer's disease (AD) frequently exhibit anomia early in the course of the disease. Current theories of naming describe lexical retrieval in visual confrontation naming as requiring processing through the semantic system before lexical access. We report on three patients with AD who demonstrated severely impoverished spontaneous speech, impaired list generation, but preserved visual confrontation naming. Extensive investigation of one of these patients revealed an impairment of semantic knowledge. Our results support previous theories that there are two routes to visual naming, one via the semantic system and one directly from the internal visual representation to the lexicon. We labeled this aphasia resulting from an impaired semantic system but a preserved direct route to the lexical system as "nonoptic aphasia" and suggest that it is the earliest language deficit in some patients with AD.