Recruiting to preclinical Alzheimer's disease clinical trials through registries

Research Attitudes Questionnaire scores and retention in a recruitment registry

BACKGROUND

Recruitment registries are maximally effective when registrants are retained to the point of referral. The Research Attitudes Questionnaire (RAQ) has previously been shown to predict research participation behaviors, including Alzheimer's disease clinical trial completion.

OBJECTIVE

To test the hypothesis that RAQ score is associated with retention behaviors in a local recruitment registry.

METHODS

Using data from the UC Irvine Consent-to-Contact Registry, a recruitment registry that enrolls adults 18 years and older, we used logistic regression to quantify the association of RAQ score and the odds of first-year non-renewal. Covariates included demographic variables, comorbidities, and recruitment source. In longitudinal analyses, we used discrete proportional hazards and Cox proportional hazards models to quantify the relationship between RAQ score and time to non-renewal and time to active withdrawal, respectively.

RESULTS

Among n = 4663 participants, we estimated that a 5-point higher baseline RAQ score was associated with a 15% lower odds of first-year non-renewal, after adjustment for potential confounding factors (OR: 0.85, 95% CI: (0.79, 0.92), p < 0.001). Older age and higher education were also associated with lower odds of non-renewal while Asian race, Hispanic ethnicity, and certain recruitment sources (e.g., doctor or friend referral) were associated with higher odds of non-renewal. Higher baseline RAQ and higher annually updated RAQ were both significantly associated with lower odds of non-renewal longitudinally. Age, education, and some recruitment sources, but not RAQ, were associated with active withdrawal.

CONCLUSIONS

Opportunities exist to identify predictors of registry retention behaviors and possible targets for intervention to improve related outcomes.

Evaluation of efficiency and effectiveness of different recruitment strategies for the FINGER-NL multidomain lifestyle intervention trial via the Dutch Brain Research Registry

INTRODUCTION

Recruitment of participants for intervention studies is challenging. We evaluated the effectiveness and efficiency of a participant recruitment campaign through an online registry for the FINGER-NL study, a multi-domain lifestyle intervention trial targeting cognitively healthy individuals aged 60-79 with dementia prevention potential. Additionally, we explored which recruitment strategy successfully reached individuals from underrepresented groups in research.

METHODS

The campaign entailed seven recruitment strategies referring to The Dutch Brain Research Registry (DBRR): (1) Facebook advertisements, (2) appearance on national television, (3) newspaper articles, (4) researcher outreach, (5) patient organizations, (6) search engines, and (7) other. For each strategy, we describe the number of individuals (a) registered, (b) potentially eligible, and (c) included in FINGER-NL. Subsequently, the efficiency, defined by the eligibility ratio (eligible/registered), and effectiveness, defined by the inclusion ratio (included/registered) were calculated. Associations between recruitment strategies and sociodemographic factors of underrepresented groups were tested with binomial logistic regressions.

RESULTS

The campaign resulted in 13,795 new DBRR registrants, of which n = 3475 were eligible (eligibility ratio = 0.25) and n = 1008 were included (inclusion ratio = 0.07). The Facebook advertisements and television appearance resulted in the highest numbers of registrants (n = 4678 and n = 2182) which translated to the highest number of inclusions (n = 288 and n = 262). The appearance on national television (eligibility ratio = 0.35), newspaper articles (0.26), and Facebook campaigns (0.26) were the most efficient strategies. The national television appearance (inclusion ratio = 0.13) was the most effective strategy. The Facebook campaign and appearance on national television performed relatively better in recruiting individuals from underrepresented groups.

DISCUSSION

A multipronged recruitment campaign via a national online recruitment registry is efficient and effective in recruiting and prescreening an adequate number of individuals aged 60-79 years with prevention potential for a multi-site intervention trial within a limited time frame of 15 months. Social media advertisements and television are preferred strategies to recruit individuals from underrepresented groups.

Highlights

An online brain research registry recruited eligible participants successfully.Mass media recruitment strategies are efficient for reaching large numbers.Direct recruitment through researchers and patient organizations seems more effective.Online registries offer automated prescreening and alternatives for screen-failures.Tailored strategies are needed to reach underrepresented groups to improve diversity.

Ethical issues in genomics research in persons with Alzheimer's Disease/Alzheimer's Disease-related dementia (AD/ADRD): a systematic review

INTRODUCTION

Given the growing number of Alzheimer's Disease and Alzheimer's Disease Related Dementias (AD/ADRD) genomics research projects and the vulnerabilities of study participants, it is critical to evaluate the literature on the ethical challenges in such studies to ensure high ethical standards.

METHODS

We conducted a systematic review of the literature on ethical issues in AD/ADRD genomics research. We searched Embase, PsycINFO, CiNAHL, Scopus, and Ovid Medline for empirical and normative papers published in peer-reviewed journals on the ethical issues involved in conducting genomics research among persons with AD/ADRD. We used ethical principles from an existing framework as a priori codes to categorize the ethical issues and adapted another framework of Dementia Research Ethical Issues (DREI) as subcategories for our synthesis. We used the 2021 PRISMA guidelines to guide our study.

RESULTS

We screened 5,509 papers and included 27 of these papers in the systematic review after deduplication, title, and full-text review. The papers contained 109 ethical issues that were mapped against 42 out of 75 relevant DREIs. The highest number of DREIs were mapped to "respect for persons and communities", "favorable risk-benefit ratio", "informed consent" and "scientific validity". The least mapped principles to the DREIs were "fair participant selection", "independent review", "social value", and "collaborative partnership".

CONCLUSION

Our review showed that there is a dearth of literature on the ethical principles of "fair participant selection", "independent review", "social value" and "collaborative partnership" in genomics research on AD/ADRDs. It is difficult to draw firm conclusions from the distribution of attention paid to specific principles because these may only reflect the concerns of AD/ADRD genomics research ethicists in high-income countries. There is need for more research on the ethics of AD/ADRD genomics research in low and middle-income countries for a more balanced account of the important ethical considerations in this field.

Comparing research attitudes in Down syndrome and non-Down syndrome research decision-makers

INTRODUCTION

Recruitment challenges in people with and without Down syndrome (DS) can delay research progress and risk sample bias. This study identified and quantified differences in research attitudes across populations of research enrollment decision-makers for individuals with and without DS.

METHODS

We performed analyses using data from two registries: the University of California, Irvine Consent-to-Contact (C2C) Registry and DS-Connect. The former represented a sample of non-DS decision-makers (N = 4818), while for the latter, we excluded individuals with DS, leaving a population of DS family decision-makers (N = 976). We assessed scores on the Research Attitudes Questionnaire (RAQ) between DS and non-DS decision-makers. We compared total RAQ scores using linear regression and assessed item-level RAQ differences using proportional odds regression.

RESULTS

Mean total RAQ scores were not statistically different between decision-makers in the two registries, after adjusting for age, sex, race and ethnicity, education, and the coronavirus disease 2019 (COVID-19) time frame (Est. Diff = 0.11, 95% confidence interval [CI]: -0.22, 0.43; p = 0.531). However, in a pre-specified analysis, we did find evidence of differential attitudes on item-level RAQ scores. Specifically, decision-makers for participants with DS had increased odds of a more favorable response to the question of responsibility to help others (DS vs. non-DS: odds ratio [OR] = 1.26, 95% CI: 1.08, 1.48) and decreased odds of a more favorable response to the question regarding the belief that medical research would find cures for major diseases during their lifetime (DS vs. non-DS: OR = 0.77, 95% CI: 0.66, 0.90).

DISCUSSION

Our findings provide insights for researchers to develop strategies for recruiting individuals with and without DS into clinical research. The observed item-level differences warrant further investigation to instruct precise recruitment strategies.

Highlights

Research attitudes between decision-makers for individuals with Down syndrome (DS) and decision-makers without DS were observed to be similar on average.Item-level differences in research attitudes were observed to differ for DS and non-DS decision-makers.These results can help facilitate precise recruitment strategies for populations with DS.

Aducanumab for Alzheimer's disease: Observations and opportunities

OBJECTIVE

To analyse the overseas approval of aducanumab for Alzheimer's disease, in order to derive lessons of potential interest to individuals and groups involved in dementia drug development and regulation in Australia.

CONCLUSIONS

Opportunities were identified regarding optimising clinical trial design and solidifying regulatory responsibilities. Increased awareness of the attitudes and needs of patients and patient advocacy organisations would likely improve the patient-clinician alliance. Incorporation of these factors into research design has the potential to improve patient satisfaction with outcomes.

Recruiting Persons with Dementia and Caregivers in a Clinical Trial: Dyads Perceptions

Recruitment for dementia research is challenging and costly. Using Ajzen's Theory of Planned Behavior we explored attitudes, perceived norms, and perceived behavioral control of persons living with dementia (PLWD) and their caregivers who participated in one clinical trial to better understand factors that influence dyads' decisions to enroll. We conducted semi-structured telephone interviews with 12 PLWD and 9 caregivers and utilized directed content analysis. Categories connected with positive attitudes about study enrollment were personal desires of wanting to learn and in-person meetings with knowledgeable staff. Additionally, participants said the money always helps in terms of the financial incentive. Participants reported enrolling to support another person (perceived norm). Study requirements were thought to be easy (perceived behavioral control). Participants highlighted the importance of flexible scheduling and study tasks being completed at their home. Findings can inform future recruitment efforts and should be investigated as effective recruitment methods in other clinical trials.

Subjective Cognitive Decline in a Registry Sample: Relation to Psychiatric History, Loneliness, and Personality

BACKGROUND

With the increasing focus on prevention of Alzheimer's disease, there is need for characterization of preclinical populations. Local participant registries offer an opportunity to facilitate research engagement via remote data collection, inform recruitment, and characterize preclinical samples, including individuals with subjective cognitive decline.

OBJECTIVES

We sought to characterize subjective cognitive decline in a registry sample, as related to psychiatric history and related variables, including personality and loneliness, quality of life, and factors related to dementia risk (e.g., family history of dementia).

DESIGN, SETTING, PARTICIPANTS

Participants were 366 individuals (mean age=67.2 (range 50-88), 65% female, 94% white, 97% non-Hispanic or Latino, 82% with at least a bachelor's degree) with no reported history of mild cognitive impairment or dementia. All participants had expressed interest in research, primarily via community outreach events and prior research involvement. Data was collected via electronic surveys, distributed using REDCap. Electronic questionnaires included questions on demographic variables, subjective cognitive decline, quality of life, loneliness, and personality.

RESULTS

There was a high prevalence of risk factors for dementia in the registry sample (68% with family history of dementia, 31% with subjective cognitive decline). Subjective cognitive decline was more common in women and associated with history of depression, but not with family history of dementia. Subjective cognitive decline was also associated with lower conscientiousness and lower emotional stability, as well as higher loneliness and lower quality of life. Among participants who endorsed a psychiatric history, most reported onset more than 10 years prior, rather than within the last 10 years.

CONCLUSIONS

Subjective cognitive decline in a registry sample may be more strongly associated with longstanding psychiatric and personality variables, rather than family history of dementia, adding to the literature on characterization of subjective cognitive decline across different settings. These findings highlight the acceptability of remote data collection and the potential of registries to inform recruitment by characterizing registrants, which may help to stratify dementia risk and match participants to eligible trials.

Diversifying Recruitment Registries: Considering Neighborhood Health Metrics

BACKGROUND

Disparities in clinical research participation perpetuate broader health disparities. Recruitment registries are novel tools to address known challenges in accrual to clinical research. Registries may accelerate accrual, but the utility of these tools to improve generalizability is unclear.

OBJECTIVE

To examine the diversity of a local on-line recruitment registry using the Area Deprivation Index (ADI), a publicly available metric of neighborhood disadvantage.

DESIGN

Retrospective analysis.

SETTING

Data were collected in the University of California Irvine Consent-to-Contact Registry.

PARTICIPANTS

We categorized N=2,837 registry participants based on the ADI decile (collapsed into quintiles) using a state-based rankings.

MEASUREMENTS

We examined the proportion of enrollees per ADI quintile and quantified the demographics of these groups. We assessed willingness to participate in studies involving unique research procedures among the ADI groups.

RESULTS

Although registry enrollees represented the full spectrum of the ADI, they disproportionately represented less disadvantaged neighborhoods (lowest to highest quintiles: 42%, 30%, 15%, 6%, 7%). Compared to participants from less disadvantaged neighborhoods, participants from more disadvantaged neighborhoods were more often female, of non-white race, and Hispanic ethnicity. Despite demographic differences, ADI groups were observed to have similar willingness to participate in research studies.

CONCLUSIONS

People from more disadvantaged neighborhoods may be underrepresented in recruitment registries, increasing the risk that they will be underrepresented when using these tools to facilitate prospective recruitment to clinical research. Once enrolled in registries, participants from more disadvantaged neighborhoods may be equally willing to participate in research. Efforts to increase representation of participants from disadvantaged neighborhoods in registries could be an important first step toward increasing the generalizability of clinical research.

Early Implementation and Evaluation of StepUp for Dementia Research: An Australia-Wide Dementia Research Participation and Public Engagement Platform

Recruiting participants for dementia research takes time. For those who are interested, opportunities to participate can be ad hoc. Delays in finding the right participants can result in studies taking longer to deliver, often requiring funding extensions, and ultimately increasing the cost and limiting the effectiveness of research and evaluation. To address these issues, a digital platform, StepUp for Dementia Research, was developed in 2019 and evaluated through ongoing data analytics, researcher feedback and annual volunteer surveys in 2019 and 2021. Using innovative matching technology, StepUp provides volunteers with an opt-in, secure way of registering interest in dementia studies and allows researchers to access matched volunteers in Australia. As of June 2021, 1070 volunteers registered (78% female), and 25 organizations became ‘champions’ for StepUp promotion. Of 122 registered researchers, 90 completed training. Forty studies from 17 research/health institutions recruited participants using StepUp. The evaluation demonstrated program feasibility and recruitment efficiency with a high level of satisfaction from users. Evaluation outcomes highlighted disparities in public participation in dementia research (e.g., gender, education and race/ethnicity) and provided valuable insights for further enhancements of StepUp. A concerted and strategic effort is needed by leading registries such as StepUp to ensure narrowing volunteer participation gaps in dementia research.

Asian Americans and Pacific Islanders' perspectives on participating in the CARE recruitment research registry for Alzheimer's disease and related dementias, aging, and caregiving research

INTRODUCTION

This study elicited Asian Americans and Pacific Islanders' (AAPI) perspectives about recruitment strategies/messaging for participation in an aging, Alzheimer's disease and related dementias (ADRD), and caregiving research recruitment registry.

METHODS

Using a mixed methods design, CARE (Collaborative Approach for AAPI Research and Education) conducted 14 focus groups (N = 123) with AAPI cultural groups (Asian Indian, Chinese, Filipino, Japanese, Korean, Samoan, Vietnamese) in different languages. Descriptive statistics and thematic qualitative analyses were conducted.

RESULTS

Mean age of participants was 54 years (median: 61; range 18-80), 66% were female, and 81% were foreign-born. Themes of consideration for recruitment emerged: (1) culturally/linguistically appropriate outreach in culturally specific spaces, (2) motivations for research participation, and (3) approaches to outreach and recruitment methods. Within each of these themes, there were ethnic differences in specific strategies/approaches reflected as subthemes.

DISCUSSION

Recruitment and messaging strategies should be tailored uniquely for each targeted AAPI group, with a thorough understanding of the cultural/linguistic factors that facilitate research participation to increase AAPI participation in ADRD, aging, and caregiver-related research. .

Real-world Site Experiences With GeneMatch: The Role of a Recruitment-related Registry in the Context of Local Site Effort to Support Alzheimer Disease Prevention Research

BACKGROUND

Registries have been proposed as a novel way to accelerate targeted recruitment for Alzheimer disease prevention clinical trials. However, there are limited data regarding registry effectiveness at accelerating recruitment and enrollment in research opportunities. This manuscript explores one site's experience with GeneMatch, a novel genetic registry for Alzheimer disease research.

METHODS

Referrals from GeneMatch to the site were tracked to understand the demographics of those referred and ultimate research enrollment outcomes. Referrals were cross-referenced with the site's existing recruitment database, to better understand the role of GeneMatch in the context of existing recruitment efforts.

RESULTS

GeneMatch referred 86 individuals to the site, resulting in 54 individuals coming into the site to pursue research involvement further. The majority of referrals (52/86, 60.47%) did not have prior contact with the site about research engagement, and having prior site contact did not significantly relate to engaging in on-site research.

CONCLUSIONS

GeneMatch helped identify new individuals for participation in Alzheimer disease prevention studies. Results highlight the value of continuing local site-level efforts while also taking advantage of registries to enhance research recruitment. Ongoing efforts to further develop these and other novel strategies for outreach and engagement are much needed.

Pilot study of an Alzheimer's disease risk assessment program in a primary care setting

INTRODUCTION

The goal of this study was to pilot a referral-based cognitive screening and genetic testing program for Alzheimer's disease (AD) risk assessment in a primary care setting.

METHODS

Primary care providers (PCPs; N = 6) referred patients (N = 94; M = 63 years) to the Rhode Island Alzheimer's Disease Prevention Registry for apolipoprotein E (APOE) genotyping and cognitive screening. PCPs disclosed test results to patients and counseled them about risk factor modification.

RESULTS

Compared to the Registry as a whole, participants were younger, more likely to be non-White, and had lower cognitive screening scores. Mild cognitive impairment participants correctly reported a higher perceived risk of developing AD. Patients who recalled being counseled about modifiable risk factors were more likely to report positive health behavior changes.

DISCUSSION

A referral-based program for cognitive and genetic AD risk assessment in a primary care setting is feasible, acceptable to patients, and yielded a more demographically diverse sample than an AD prevention registry.

Prescreening for European Prevention of Alzheimer Dementia (EPAD) trial-ready cohort: impact of AD risk factors and recruitment settings

BACKGROUND

Recruitment is often a bottleneck in secondary prevention trials in Alzheimer disease (AD). Furthermore, screen-failure rates in these trials are typically high due to relatively low prevalence of AD pathology in individuals without dementia, especially among cognitively unimpaired. Prescreening on AD risk factors may facilitate recruitment, but the efficiency will depend on how these factors link to participation rates and AD pathology. We investigated whether common AD-related factors predict trial-ready cohort participation and amyloid status across different prescreen settings.

METHODS

We monitored the prescreening in four cohorts linked to the European Prevention of Alzheimer Dementia (EPAD) Registry (n = 16,877; mean ± SD age = 64 ± 8 years). These included a clinical cohort, a research in-person cohort, a research online cohort, and a population-based cohort. Individuals were asked to participate in the EPAD longitudinal cohort study (EPAD-LCS), which serves as a trial-ready cohort for secondary prevention trials. Amyloid positivity was measured in cerebrospinal fluid as part of the EPAD-LCS assessment. We calculated participation rates and numbers needed to prescreen (NNPS) per participant that was amyloid-positive. We tested if age, sex, education level, APOE status, family history for dementia, memory complaints or memory scores, previously collected in these cohorts, could predict participation and amyloid status.

RESULTS

A total of 2595 participants were contacted for participation in the EPAD-LCS. Participation rates varied by setting between 3 and 59%. The NNPS were 6.9 (clinical cohort), 7.5 (research in-person cohort), 8.4 (research online cohort), and 88.5 (population-based cohort). Participation in the EPAD-LCS (n = 413 (16%)) was associated with lower age (odds ratio (OR) age = 0.97 [0.95-0.99]), high education (OR = 1.64 [1.23-2.17]), male sex (OR = 1.56 [1.19-2.04]), and positive family history of dementia (OR = 1.66 [1.19-2.31]). Among participants in the EPAD-LCS, amyloid positivity (33%) was associated with higher age (OR = 1.06 [1.02-1.10]) and APOE ɛ4 allele carriership (OR = 2.99 [1.81-4.94]). These results were similar across prescreen settings.

CONCLUSIONS

Numbers needed to prescreen varied greatly between settings. Understanding how common AD risk factors link to study participation and amyloid positivity is informative for recruitment strategy of studies on secondary prevention of AD.

Constructing a Local Potential Participant Registry to Improve Alzheimer's Disease Clinical Research Recruitment

Potential participant registries are tools to address the challenge of slow recruitment to clinical research. In particular, registries may aid recruitment to secondary prevention clinical trials for Alzheimer's disease (AD), which enroll cognitively normal older individuals meeting specific genetic or biomarker criteria. Evidence of registry effectiveness is sparse, as is guidance on optimal designs or methods of conduct. We report our experiences of developing a novel local potential participant registry that implemented online enrollment and data collection. In the first year of operation, 957 individuals submitted email addresses to the registry, of whom 592 self-reported demographic, family history, and medical data. In addition, registrants provided information related to their interest and willingness to be contacted about studies. Local earned media and community education were the most effective methods of recruitment into the registry. Seventy-six (26%) of 298 registrants contacted about studies in the first year enrolled in those studies. One hundred twenty-nine registrants were invited to enroll in a preclinical AD trial, of whom 25 (18%) screened and 6 were randomized. These results indicate that registries can aid recruitment and provide needed guidance for investigators initiating new local registries.

Genomic variant sharing: a position statement

Sharing de-identified genetic variant data is essential for the practice of genomic medicine and is demonstrably beneficial to patients. Robust genetic diagnoses that inform medical management cannot be made accurately without reference to genetic test results from other patients, as well as population controls. Errors in this process can result in delayed, missed or erroneous diagnoses, leading to inappropriate or missed medical interventions for the patient and their family. The benefits of sharing individual genetic variants, and the harms of not sharing them, are numerous and well-established. Databases and mechanisms already exist to facilitate deposition and sharing of pseudonomised genetic variants, but clarity and transparency around best practice is needed to encourage widespread use, prevent inconsistencies between different communities, maximise individual privacy and ensure public trust. We therefore recommend that widespread sharing of a small number of individual genetic variants associated with limited clinical information should become standard practice in genomic medicine. Information robustly linking genetic variants with specific conditions is fundamental biological knowledge, not personal information, and therefore should not require consent to share. For additional case-level detail about individual patients or more extensive genomic information, which is often essential for clinical interpretation, it may be more appropriate to use a controlled-access model for data sharing, with the ultimate aim of making as much information as open and de-identified as possible with appropriate consent.

Genomic variant sharing: a position statement

Sharing de-identified genetic variant data is essential for the practice of genomic medicine and is demonstrably beneficial to patients. Robust genetic diagnoses that inform medical management cannot be made accurately without reference to genetic test results from other patients, as well as population controls. Errors in this process can result in delayed, missed or erroneous diagnoses, leading to inappropriate or missed medical interventions for the patient and their family. The benefits of sharing individual genetic variants, and the harms of not sharing them, are numerous and well-established. Databases and mechanisms already exist to facilitate deposition and sharing of pseudonomised genetic variants, but clarity and transparency around best practice is needed to encourage widespread use, prevent inconsistencies between different communities, maximise individual privacy and ensure public trust. We therefore recommend that widespread sharing of a small number of individual genetic variants associated with limited clinical information should become standard practice in genomic medicine. Information robustly linking genetic variants with specific conditions is fundamental biological knowledge, not personal information, and therefore should not require consent to share. For additional case-level detail about individual patients or more extensive genomic information, which is often essential for clinical interpretation, it may be more appropriate to use a controlled-access model for data sharing, with the ultimate aim of making as much information as open and de-identified as possible with appropriate consent.

Nonlinear Distributional Mapping (NoDiM) for harmonization across amyloid-PET radiotracers

INTRODUCTION

There is a growing need in clinical research domains for direct comparability between amyloid-beta (Aβ) Positron Emission Tomography (PET) measures obtained via different radiotracers and processing methodologies. Previous efforts to provide a common measurement scale fail to account for non-linearities between measurement scales that can arise from these differences. We introduce a new application of distribution mapping, based on well established statistical orthodoxy, that we call Nonlinear Distribution Mapping (NoDiM). NoDiM uses cumulative distribution functions to derive mappings between Aβ-PET measurements from different tracers and processing streams that align data based on their location in their respective distributions.

METHODS

Utilizing large datasets of Florbetapir (FBP) from the Alzheimer's Disease Neuroimaging Initiative (n = 349 female (%) = 53) and Pittsburgh Compound B (PiB) from the Harvard Aging Brain Study (n = 305 female (%) = 59.3) and the Australian Imaging, Biomarker & Lifestyle Flagship Study of Ageing (n = 184 female (%) = 53.3), we fit explicit mathematical models of a mixture of two normal distributions, with parameter estimates from Gaussian Mixture Models, to each tracer's empirical data. We demonstrate the accuracy of these fits, and then show the ability of NoDiM to transform FBP measurements into PiB-like units.

RESULTS

A mixture of two normal distributions fit both the FBP and PiB empirical data and provides a strong basis for derivation of a transfer function. Transforming Aβ-PET data with NoDiM results in FBP and PiB distributions that are closely aligned throughout their entire range, while a linear transformation does not. Additionally the NoDiM transform better matches true positive and false positive profiles across tracers.

DISCUSSION

The NoDiM transformation provides a useful alternative to the linear mapping advocated in the Centiloid project, and provides improved correspondence between measurements from different tracers across the range of observed values. This improved alignment enables disparate measures to be merged on to continuous scale, and better enables the use of uniform thresholds across tracers.

Using a birth cohort to study brain health and preclinical dementia: recruitment and participation rates in Insight 46

OBJECTIVE

Identifying and recruiting people with early pre-symptomatic Alzheimer's disease to neuroimaging research studies is increasingly important. The extent to which results of these studies can be generalised depends on the recruitment and representativeness of the participants involved. We now report the recruitment and participation patterns from a neuroscience sub-study of the MRC National Survey of Health and Development, "Insight 46". This study aimed to recruit 500 participants for extensive clinical and neuropsychological testing, and neuroimaging. We investigate how sociodemographic factors, health conditions and health-related behaviours predict participation at different levels of recruitment.

RESULTS

We met our target recruitment (n = 502). Higher educational attainment and non-manual socio-economic position (SEP) were consistent predictors of recruitment. Health-related variables were also predictive at every level of recruitment; in particular higher cognition, not smoking and better self-rating health. Sex and APOE-e4 status were not predictors of participation at any level. Whilst recruitment targets were met, individuals with lower SEP, lower cognition, and more health problems are under-represented in Insight 46. Understanding the factors that influence recruitment are important when interpreting results; for Insight 46 it is likely that health-related outcomes and life course risks will under-estimate those seen in the general population.

Patient Engagement: The Fundació ACE Framework for Improving Recruitment and Retention in Alzheimer's Disease Research

Alzheimer's disease (AD) research is at a critical time. The global society is increasingly aware of the frightening rate of growth of the human and financial burden caused by this condition and of the urgent need to halt its progression. Consequently, the scientific community holds great responsibility to quickly put in place and optimize the machinery necessary for testing new treatments or interventions. In this context demand for participants for AD research is at an all-time high. In this review, we will focus on a methodological factor that is increasingly recognized as a key factor that shapes trial populations and affects validity of results in clinical trials: patient engagement, recruitment, and retention. We outline specific problems relevant to patient engagement in AD including recruiting enough participants, difficulties in participant retention, ensuring the recruited sample is representative of the general AD population, the burden of screening failures, and new challenges related to recruiting in preclinical disease. To address the urgent need for more research studying the applicability and cost-effectiveness of different recruitment strategies across different settings and nationalities, we describe the Models of Patient Engagement for Alzheimer's Disease (MOPEAD) project, a public-private partnership promoted by the Innovative Medicine Initiative (IMI), which will provide a large multinational quantitative analysis comparing different innovative recruitment models. We also discuss strategies that address each problem and draw on the experience of Fundació ACE to argue that focusing resources on comprehensive AD centers that offer coordinated clinical and social care and participate in basic and clinical research, is an effective and efficient way of implementing many of the discussed strategies.