Racial and ethnic differences in plasma biomarker eligibility for a preclinical Alzheimer's disease trial.

INTRODUCTION: In trials of amyloid-lowering drugs for Alzheimer's disease (AD), differential eligibility may contribute to under-inclusion of racial and ethnic underrepresented groups. We examined plasma amyloid beta 42/40 and positron emission tomography (PET) amyloid eligibility for the ongoing AHEAD Study preclinical AD program (NCT04468659). METHODS: Univariate logistic regression models were used to examine group differences in plasma and PET amyloid screening eligibility. RESULTS: Of 4905 participants screened at time of analysis, 1724 were plasma eligible to continue in screening: 13.3% Hispanic Black, 24.7% Hispanic White, 20.8% non-Hispanic (NH) Asian, 24.7% NH Black, and 38.9% NH White. Plasma eligibility differed across groups in models controlling for covariates (odds ratio from 1.9 to 4.0 compared to the NH White reference group, P < 0.001). Among plasma eligible participants, PET eligibility did not differ by group. DISCUSSION: These results suggest that prevalence of brain amyloid pathology differed, but that eligibility based on plasma was equally effective across racial and ethnic group members. HIGHLIGHTS: Plasma amyloid eligibility is lower in underrepresented racial and ethnic groups. In plasma eligible adults, positron emission tomography eligibility rates are similar across race and ethnicity. Plasma biomarker tests may be similarly effective across racial and ethnic groups.

Immediate Reactions to Alzheimer Biomarker Disclosure in Cognitively Unimpaired Individuals in a Global Truncated Randomized Trial.

Background and Objectives: Preclinical Alzheimer disease (AD) trials simultaneously test candidate treatments and the implications of disclosing biomarker information to cognitively unimpaired individuals. Methods: The EARLY trial was a randomized, double-blind, placebo-controlled, phase 2b/3 study conducted in 143 centers across 14 countries from November 2015 to December 2018 after being stopped prematurely because of treatment-related hepatotoxicity. Participants age 60-85 years deemed cognitively unimpaired were disclosed an elevated or not elevated brain amyloid result by a certified clinician. Among 3,686 participants, 2,066 underwent amyloid imaging, 1,394 underwent CSF biomarker assessment, and 226 underwent both. Among biomarker-tested participants with at least one change score on an outcome of interest, 680 with elevated and 2,698 with not elevated amyloid were included in this analysis. We compared the Geriatric Depression Scale (GDS), the State-Trait Anxiety Scale (STAI), and the Columbia Suicide Severity Rating Scale (CSSRS) before disclosure between amyloid groups. After disclosure, we assessed for differences in the Impact of Events Scale (IES, collected 24-72 hours after disclosure), a measure of intrusive thoughts. Additional scales included the Concerns for AD scale. Results: Among 3378 included participants, the mean (SD) age was 69.0 (5.3); most were female (60%) and White race (84%). No differences were observed before disclosure between participants with elevated and not elevated amyloid for the GDS, STAI, or CSSRS. Participants with elevated amyloid demonstrated higher Concerns for AD scores compared with participants with not elevated amyloid before disclosure. Participants with elevated amyloid demonstrated higher IES scores (9.6 [10.8] vs 5.1 [8.0]) after disclosure and increased Concerns about AD. Patterns of reactions (elevated vs not elevated) were similar for biomarker modalities, although scores were lower among those undergoing CSF compared with PET testing. Although score differences were apparent comparing geographical regions, patterns of group differences were similar. Discussion: Although sample bias must be considered, these results suggest that amyloid disclosure resulted in increased perceived risk and mild distress in those learning an elevated result. Although this study did not assess psychological safety, observed associations intrusive thoughts and distress could be important considerations in the future clinical practice.

Study Partner Type and Adverse Event Reporting in Mild-to-Moderate Alzheimer's Disease Clinical Trials.

Background: In randomized clinical trials (RCTs), monitoring adverse events (AEs) and serious AEs (SAEs) is critical. All Alzheimer's disease (AD) RCTs require participants to enroll with a study partner. Objective: We examined AE reporting rates in mild-to-moderate AD trials and their associations with study partner type. Methods: We estimated AE reporting rates using placebo data from seven independent RCTs conducted by the Alzheimer's Disease Cooperative Study. We assessed the heterogeneity of reporting rates as a function of visits using generalized estimating equations. In the primary analysis, we tested the hypotheses that the rates of reporting differed by study partner type and time they spent with the participant weekly using Poisson regression with robust variance estimation. In all regression models, log-transformed total patient years was included. Results: The estimated reporting rates were 2.83 (95% CI: 2.66, 3.02), 1.18 (95% CI: 1.09, 1.28), 0.23 (95% CI: 0.19, 0.27), and 0.28 (95% CI: 0.24, 0.33) events per participant year for grade 1-3 AEs and SAEs, respectively. We estimated that greater number of visits per year was associated with increased reporting for grade 1-2 AEs and SAEs. We did not find evidence to suggest that AE reporting differed by study partner type or by time the study partner spent with the participant. Conclusions: Study partner type and time the study partner spent with the participant did not appear to impact AE reporting. Estimated reporting rates may be useful to evaluate safety in future studies, particularly those with no control arm and similar visit frequencies.

Post-disclosure distress among racial and ethnic groups in a preclinical AD trial.

INTRODUCTION: Trialists need a thorough understanding of whether reactions to Alzheimer's disease (AD) biomarker information differ among racial and ethnic groups in preclinical AD trials. METHODS: We used data from the Anti-Amyloid Treatment in Asymptomatic Alzheimer's Disease Study to analyze cognitively unimpaired participants' responses on the Impact of Event Scale (IES) 24 to 72 hours after amyloid disclosure. We fit a linear regression model to test whether mean IES scores differed among participants from specific racial and ethnic groups. We considered potential effect modification by amyloid status. RESULTS: Reactions to disclosure did not significantly differ among participant groups based on self-reported race and ethnicity. Although the results were not significant when stratified by amyloid status, all racial and ethnic groups except for participants self-reporting Hispanic/Latino ethnicity were observed to have higher mean IES in the elevated amyloid group. DISCUSSION: These results support continued use of current disclosure methods in preclinical AD trials.

Apolipoprotein E Genetic Testing in a New Age of Alzheimer Disease Clinical Practice.

The recent FDA approval of amyloid-lowering drugs is changing the landscape of Alzheimer disease (AD) clinical practice. Previously, apolipoprotein E (APOE) genetic testing was not recommended in the care of people with AD because of limited clinical utility. With the advent of amyloid-lowering drugs, APOE genotype will play an important role in guiding treatment recommendations. Recent clinical trials have reported strong associations between APOE genotype and the safety and possibly the efficacy of amyloid-lowering drugs. Therefore, a clinical workflow that includes biomarker and genetic testing should be implemented to provide patients with the opportunity to make informed decisions and instruct safety monitoring for clinicians. Pretest consent, education, and counseling will be an essential aspect of this process for patients and their family members to understand the implications of these tests and their results. Given that the approved amyloid-lowering drugs are indicated for patients with mild cognitive impairment or mild dementia with biomarker evidence of AD, biomarker testing should be performed before genetic testing and genetic testing should only be performed in patients interested in treatment with amyloid-lowering drugs. It is also important to consider other implications of genetic testing, including burden on and need for additional training for clinicians, the role of additional providers, and the potential challenges for patients and families.

Examining Utilization of Formal Supports and Related Impacts on Overall Well-Being Among East Asian American Family Caregivers of Persons With Dementia: A Mixed-Methods Study.

BACKGROUND AND OBJECTIVES: Although East Asian American family caregivers are known to underutilize formal support services, there is a lack of evidence regarding the associations of formal service utilization with caregivers' well-being. This study examined the prevalence of different types of home-and community-based formal service utilization among Korean and Chinese American family caregivers of persons with dementia and how utilization of such services was associated with their well-being. We also explored their overall experience in accessing and utilizing formal dementia support services and programs. RESEARCH DESIGN AND METHODS: We employed a convergent mixed-methods study design. In a convenience sampling method, we recruited 62 family caregivers. Logistic regression and thematic analysis were utilized to analyze data. RESULTS: The results showed in-home services were mostly utilized among family caregivers of these ethnic groups. Out of 9 different support services, those who utilized nutrition programs and case management were more likely to report higher overall well-being. Four themes were developed: (1) awareness of formal support services but uncertainty on how to access them, (2) language barriers imposing additional challenges in accessing formal support services, (3) traveling to access culturally appropriate services, and (4) desire for culturally tailored medical and long-term care services. DISCUSSION AND IMPLICATIONS: Findings from this study suggest the importance of case management services to overcome barriers to accessing and utilizing a wide range of formal support services and provision of culturally appropriate food in formal support services to increase East Asian American family caregivers' utilization of long-term care services.

Brain Health Registry Study Partner Portal: Novel infrastructure for digital, dyadic data collection.

BACKGROUND: In Alzheimer's disease (AD) research, subjective reports of cognitive and functional decline from participant-study partner dyads is an efficient method of assessing cognitive impairment and clinical progression. METHODS: Demographics and subjective cognitive/functional decline (Everyday Cognition Scale [ECog]) scores from dyads enrolled in the Brain Health Registry (BHR) Study Partner Portal were analyzed. Associations between dyad characteristics and both ECog scores and study engagement were investigated. RESULTS: A total of 10,494 BHR participants (mean age = 66.9 ± 12.16 standard deviations, 67.4% female) have enrolled study partners (mean age = 64.3 ± 14.3 standard deviations, 49.3% female), including 8987 dyads with a participant 55 years of age or older. Older and more educated study partners were more likely to complete tasks and return for follow-up. Twenty-five percent to 27% of older adult participants had self and study partner-report ECog scores indicating a possible cognitive impairment. DISCUSSION: The BHR Study Partner Portal is a unique digital tool for capturing dyadic data, with high impact applications in the clinical neuroscience and AD fields. Highlights The Brain Health Registry (BHR) Study Partner Portal is a novel, digital platform of >10,000 dyads. Collection of dyadic online subjective cognitive and functional data is feasible. The portal has good usability as evidenced by positive study partner feedback. The portal is a potential scalable strategy for cognitive impairment screening in older adults.

Eligibility Rates among Racially and Ethnically Diverse US Participants in Phase 2 and Phase 3 Placebo-Controlled, Double-Blind, Randomized Trials of Lecanemab and Elenbecestat in Early Alzheimer Disease.

OBJECTIVE: Many factors contribute to inadequate diversity in Alzheimer disease (AD) clinical trials. We evaluated eligibility rates among racial and ethnic groups at US sites in large global multisite trials in early AD. METHODS: Using screening data from 4 randomized, double-blind, placebo-controlled clinical trials in early AD, we assessed rates of eligibility among racial and ethnic groups controlling for other demographic covariates. Each trial incorporated positron emission tomography and/or cerebrospinal fluid to evaluate brain amyloid pathology, as well as typical eligibility criteria used in early AD trials. RESULTS: Across the trials, 10,804 US participants were screened: 193 (2%) were of Hispanic ethnicity and Black race, 2,624 (25%) were of Hispanic ethnicity and White race, 118 (1%) were of non-Hispanic ethnicity (NH) and Asian race, 696 (7%) were of NH ethnicity and Black race, and 7,017 (65%) were of NH ethnicity and White race. Data from 156 participants who did not fit into these categories were excluded. Accounting for age, sex, and trial and using NH White participants as a reference group, we observed higher probabilities of ineligibility for amyloid biomarker criteria among Hispanic Black (odds ratio [OR] = 3.20, 95% confidence interval [CI] = 2.11-4.88), Hispanic White (OR = 4.15, 95% CI = 3.58-4.83), NH Asian (OR = 2.35, 95% CI = 1.23-4.55), and NH Black (OR = 3.75, 95% CI = 2.80-5.06) participants. INTERPRETATION: Differential eligibility may contribute to underrepresentation of some minoritized racial and ethnic groups in early AD trials. Amyloid biomarker eligibility is a requirement to confirm the diagnosis of AD and for treatment with amyloid-lowering drugs and differed among racial and ethnic groups. ANN NEUROL 2024;95:288-298.

Retention of American Indian and Alaska Native participants in the National Alzheimer's Coordinating Center Uniform Data Set.

INTRODUCTION: The number of American Indian and Alaska Native (AI/AN) elders is expected to double by 2060. Thus it is imperative to retain AI/AN participants in longitudinal research studies to identify novel risk factors and potential targets for intervention for Alzheimer's disease and related dementias in these communities. METHODS: The National Alzheimer's Coordinating Center houses uniformly collected longitudinal data from the network of National Institute on Aging (NIA)-funded Alzheimer's Disease Research Centers (ADRCs). We used logistic regression to quantify participant retention at 43 ADRCs, comparing self-identified AI/AN participants to non-Hispanic White (NHW) participants, adjusting for potential confounding factors including baseline diagnosis, age, sex, education, and smoking. RESULTS: The odds of AI/AN participant retention at the first follow-up visit were significantly lower than those for NHW participants (adjusted odds ratio [aOR]: 0.599; 95%: 0.46-0.78; p < 0.001). DISCUSSION: These results suggest the need for improved strategies to retain AI/AN participants, perhaps including improved researcher-community relationships and community engagement and education. HIGHLIGHTS: American Indian and Alaska Native (AI/AN) research participants were retained to the first follow-up appointment at lower rates than non-Hispanic White (NHW) participants. AI/AN participants are retained at lower rates than NHW participants for long-term follow-up. The majority of AI/AN participants were not retained to the second follow-up visit.

Effects of informant replacement in Alzheimer's disease clinical trials.

INTRODUCTION: Alzheimer's disease (AD) trials require enrollment with an informant. METHODS: We assessed relationships between informant replacement and Alzheimer's Disease Cooperative Study Activities of Daily Living (ADCS-ADL) scores across four AD trials. Using generalized estimating equations, we examined associations between replacement and change in ADCS-ADL between successive visits. We used analysis of covariance to estimate the association between replacement and 18-month change from baseline, and an F-test to compare the variance of this change. RESULTS: Among 1336 participants, 63 (≈5%) experienced replacement. Between-visit mean change in ADCS-ADL was 2.44 points lower comparing replacement to stable informants (95% confidence interval [CI]: -3.91, -0.98). The difference in between-visit mean absolute change was 2.38 points (95% CI: 1.24, 3.52). Replacement was not significantly associated with an 18-month change from baseline. The ratio of variances (replacement/stable) was 1.80 (95% CI: 1.19, 2.99). DISCUSSION: Informant replacement is associated with bias and increased variability between visits and increased variance for overall ADCS-ADL.

Estimating attrition in mild-to-moderate Alzheimer's disease and mild cognitive impairment clinical trials.

BACKGROUND: Participant retention is a key factor that affects clinical trial integrity. Trial protocols estimate attrition as a function of sample size calculations. Alzheimer's disease (AD) is an area of active treatment development. We aimed to quantify the association between trial duration and completion rates and provide guidance for estimating attrition in AD trial protocols. METHODS: Using the Alzforum and ClinicalTrials.gov databases, we analyzed retention data from 125 mild-to-moderate AD and 12 mild cognitive impairment (MCI) clinical trials. We compared the rates of completion between trial arms (active vs. control) and ran regression models to test the hypothesis that trials with longer study duration have lower trial completion using all available data and restricting to placebo data. Our primary outcome was the odds of trial completion for a 6-month increase in trial duration. From the regression model, we estimated the proportion of participants completing 6-, 12-, and 18-month trials. RESULTS: We found that 21 (17%) mild-to-moderate AD trials and 1 (8%) MCI trial demonstrated greater dropout in treatment compared to placebo arms. For every 6-month increase in trial duration, there was a 27% decrease in the odds of trial completion (OR = 0.73; 95% CI 0.66, 0.81; p < 0.001) among participants in mild-to-moderate AD trials and a 55% decrease (OR = 0.45; 95% CI 0.36, 0.57; p < 0.001) among participants in MCI trials. The proportion of participants in the placebo group completing 6-, 12-, and 18-month trials were estimated to be 85.2%, 80.0%, and 73.3% for mild-to-moderate AD trials and 91.9%, 84.2%, and 71.3% for MCI trials, respectively. CONCLUSIONS: Longer duration trials may be underpowered to demonstrate estimated treatment effects and may suffer from a greater risk of bias than do shorter trials.

Research Attitude and Interest among Cancer Survivors with or without Cognitive Impairment.

BACKGROUND: We examined the research attitudes and willingness to participate in clinical research among cancer survivors with varying degrees of cognitive function. METHODS: This is a secondary analysis of data collected through the University of California Irvine Consent-to-Contact registry. Cancer survivors completed the Cognitive Function Instrument (CFI), the Research Attitudes Questionnaire (RAQ), and willingness to participate (WTP) in certain research procedures. Perceived cognitive impairment (CI) was defined as the worst 20% CFI scores. RESULTS: Here, 265 CI and 909 cognitively non-impaired (CNI) participants' data were analyzed. Mean age and sex distribution were similar, with fewer non-Hispanic Whites and education years among CI participants. More CI participants self-reported past diagnoses of Alzheimer's disease, mild cognitive impairment, stroke, depression, post-traumatic stress disorder, and alcohol abuse (all p < 0.05). CI participants were significantly more interested in studies investigating approved medications (92% vs. 87%, p = 0.030), lumbar puncture (47% vs. 38%, p = 0.027), and autopsy (78% vs. 69%, p = 0.022). After removing survivors with co-existing neuropsychiatric conditions, interest in autopsy studies remained statistically higher among CI (79% vs. 69%, p = 0.022). CONCLUSIONS: Participants with cancer and CI are open to research procedures and interventions that are traditionally less utilized, which may facilitate the discovery of the pathogenesis and interventions for cancer-related cognitive impairment (CRCI).

Biomarker disclosure protocols in prodromal Alzheimer's disease clinical trials.

INTRODUCTION: The development of biomarkers for Alzheimer's disease (AD) has allowed researchers to increase sample homogeneity and test candidate treatments earlier in the disease. The integration of biomarker "screening" criteria should be met with a parallel implementation of standardized methods to disclose biomarker testing results to research participants; however, the extent to which protocolized disclosure occurs in trials is unknown. METHODS: We reviewed the literature to identify prodromal AD trials published in the past 10 years. From these, we quantified the frequency of biomarker disclosure reporting and the depth of descriptions provided. RESULTS: Of 30 published trials using positron emission tomography or cerebrospinal fluid-based amyloid positivity as an eligibility criterion, only one mentioned disclosure, with no details on methods. DISCUSSION: Possible reasons for and implications of this information gap are discussed. Recommendations are provided for trialists considering biomarker screening as part of intervention trials focused on prodromal AD. HIGHLIGHTS: Few prodromal Alzheimer's disease (AD) trial papers discuss biomarker disclosure. Disclosure has implications for participants, family members, and trial success. Disclosure must be consistently integrated and reported in prodromal AD trials. Best practice guidelines and training resources for disclosure are needed.

Centralizing prescreening data collection to inform data-driven approaches to clinical trial recruitment.

BACKGROUND: Recruiting to multi-site trials is challenging, particularly when striving to ensure the randomized sample is demographically representative of the larger disease-suffering population. While previous studies have reported disparities by race and ethnicity in enrollment and randomization, they have not typically investigated whether disparities exist in the recruitment process prior to consent. To identify participants most likely to be eligible for a trial, study sites frequently include a prescreening process, generally conducted by telephone, to conserve resources. Collection and analysis of such prescreening data across sites could provide valuable information to improve understanding of recruitment intervention effectiveness, including whether traditionally underrepresented participants are lost prior to screening. METHODS: We developed an infrastructure within the National Institute on Aging (NIA) Alzheimer's Clinical Trials Consortium (ACTC) to centrally collect a subset of prescreening variables. Prior to study-wide implementation in the AHEAD 3-45 study (NCT NCT04468659), an ongoing ACTC trial recruiting older cognitively unimpaired participants, we completed a vanguard phase with seven study sites. Variables collected included age, self-reported sex, self-reported race, self-reported ethnicity, self-reported education, self-reported occupation, zip code, recruitment source, prescreening eligibility status, reason for prescreen ineligibility, and the AHEAD 3-45 participant ID for those who continued to an in-person screening visit after study enrollment. RESULTS: Each of the sites was able to submit prescreening data. Vanguard sites provided prescreening data on a total of 1029 participants. The total number of prescreened participants varied widely among sites (range 3-611), with the differences driven mainly by the time to receive site approval for the main study. Key learnings instructed design/informatic/procedural changes prior to study-wide launch. CONCLUSION: Centralized capture of prescreening data in multi-site clinical trials is feasible. Identifying and quantifying the impact of central and site recruitment activities, prior to participants signing consent, has the potential to identify and address selection bias, instruct resource use, contribute to effective trial design, and accelerate trial enrollment timelines.

Retention of Study Partners in Longitudinal Studies of Alzheimer Disease.

BACKGROUND: Study partners are required for all participants at Alzheimer's Disease Research Centers (ADRCs). Study partners' attitudes and beliefs may contribute to missed visits and negatively impact retention of participants in longitudinal AD studies. OBJECTIVE: Study partners (N = 212) of participants (Clinical Dementia Rating® [CDR]≤2) at four ADRCs were randomly surveyed to examine their facilitators and barriers to continued participation in AD studies. METHODS: Reasons for participation were analyzed with factor analysis and regression analysis. Effects of complaints and goal fulfillment on attendance were estimated with fractional logistic models. Open-ended responses were characterized with a Latent Dirichlet Allocation topic model. RESULTS: Study partners participated for personal benefit and altruism. They emphasized personal benefits more when their participants had a CDR > 0 than when they had a CDR = 0. This difference declined with participant age. The majority of study partners rated their ADRC participation as positive and meeting their goals. Although half reported at least one complaint, very few regretted participating. Those who reported that ADRC participation fulfilled their goals or had fewer complaints were more likely to have perfect attendance. Study partners requested more feedback about test results and better management of study visits. CONCLUSION: Study partners are motivated by both personal and altruistic goals. The salience of each goal depends on their trust in researchers and the participant's cognitive status and age. Retention may improve with perceived goal fulfillment and fewer complaints. Potential areas for improving retention are providing more information about the participant's test results and better management of study visits.

Frameworks for estimating causal effects in observational settings: comparing confounder adjustment and instrumental variables.

To estimate causal effects, analysts performing observational studies in health settings utilize several strategies to mitigate bias due to confounding by indication. There are two broad classes of approaches for these purposes: use of confounders and instrumental variables (IVs). Because such approaches are largely characterized by untestable assumptions, analysts must operate under an indefinite paradigm that these methods will work imperfectly. In this tutorial, we formalize a set of general principles and heuristics for estimating causal effects in the two approaches when the assumptions are potentially violated. This crucially requires reframing the process of observational studies as hypothesizing potential scenarios where the estimates from one approach are less inconsistent than the other. While most of our discussion of methodology centers around the linear setting, we touch upon complexities in non-linear settings and flexible procedures such as target minimum loss-based estimation and double machine learning. To demonstrate the application of our principles, we investigate the use of donepezil off-label for mild cognitive impairment. We compare and contrast results from confounder and IV methods, traditional and flexible, within our analysis and to a similar observational study and clinical trial.

Asian Americans' and Pacific Islanders' preferences in recruitment strategies and messaging for participation in the CARE registry: A discrete choice experiment.

INTRODUCTION: This discrete choice experiment (DCE) identified Asian American and Pacific Islander (AAPI) adults' preferences for recruitment strategies/messaging to enroll in the Collaborative Approach for AAPI Research and Education (CARE) registry for dementia-related research. METHODS: DCE recruitment strategy/messaging options were developed in English, Chinese, Korean, and Vietnamese. AAPI participants 50 years and older selected (1) who, (2) what, and (3) how they would prefer hearing about CARE. Analyses utilized conditional logistic regression. RESULTS: Participants self-identified as Asian Indian, Chinese, Filipino, Japanese, Korean, Samoan, or Vietnamese (N = 356). Overall, they preferred learning about CARE from the healthcare community (vs. community champions and faith-based organizations), joining CARE to advance research (vs. personal experiences), and hearing about CARE through social media/instant messaging (vs. flyer or workshop/seminar). Preferences varied by age, ethnic identity, and survey completion language. DISCUSSION: DCE findings may inform tailoring recruitment strategies/messaging to engage diverse AAPI in an aging-focused research registry.

Recruitment across two decades of NIH-funded Alzheimer's disease clinical trials.

BACKGROUND: Timely accrual of a representative sample is a key factor in whether Alzheimer's disease (AD) clinical trials successfully answer the scientific questions under study. Studies in other fields have observed that, over time, recruitment to trials has become increasingly reliant on larger numbers of sites, with declines in the average per-site recruitment rate. Here, we examined the trends in recruitment over a 20-year period of NIH-funded AD clinical trials conducted by the Alzheimer's Disease Cooperative Study (ADCS), a temporally consistent network of sites devoted to interventional research. METHODS: We performed retrospective analyses of eleven ADCS randomized clinical trials. To examine the recruitment planning, we calculated the expected number of participants to be enrolled per site for each trial. To examine the actual trial recruitment rates, we quantified the number of participants enrolled per site per month. RESULTS: No effects of time were observed on recruitment planning or overall recruitment rates across trials. No trial achieved an overall recruitment rate greater than one subject per site per month. We observed the fastest recruitment rates in trials with no competition and the slowest in trials that overlapped in time. The highest recruitment rates were consistently seen early within trials and declined over the course of studies. CONCLUSIONS: Trial recruitment projections should plan for fewer than one participant randomized per site per month and consider the number of other AD trials being conducted concurrently.

Testing for Alzheimer Disease Biomarkers and Disclosing Results Across the Disease Continuum.

Three pathologic processes are characteristic of Alzheimer disease (AD): ß-amyloid, hyperphosphorylated tau, and neurodegeneration. Our understanding of AD is undergoing a transformation due to our ability to measure biomarkers of these processes across different stages of cognitive impairment. There is growing interest in using AD biomarker tests in care and research and, with this, a growing need for guidance on how to return these sensitive results to patients and participants. Here, we propose a 5-step approach informed by clinical and research experience designing and implementing AD biomarker disclosure processes, extant evidence describing how individuals react to AD biomarker information, ethics, law, and the literature on breaking bad news. The clinician should (1) determine the appropriateness of AD biomarker testing and return of results for the particular patient or research participant. If testing is appropriate, the next steps are to (2) provide pretest education and seek consent for testing from the individual and their support person, (3) administer testing, (4) return the results to the individual and their support person, and (5) follow-up to promote the recipient's well-being.