Enrollment, retention, and strategies for including disadvantaged populations in randomized controlled trials: a systematic review protocol

Abstract

Background Many randomized controlled trials fail to reach their target sample size. When coupled with the omission and underrepresentation of disadvantaged groups in randomized controlled trials, many trials fail to obtain data that accurately represents the true diversity of their target population. Policies and practices have been implemented to increase representation of disadvantaged groups in many randomized controlled trials, with some trials specifically targeting such groups. To our knowledge, no systematic review has quantified the enrollment metrics and effectiveness of inclusion and retention strategies in randomized controlled trials focused on disadvantaged populations specifically. Methods We will conduct a systematic search across EMBASE, MEDLINE, Web of Science, and CINAHL as well as grey literature, conference proceedings, research monographs, and Google Scholar from inception onwards. We will include randomized controlled trials where at least 50% of enrolled participants are considered to be disadvantaged, as per the RCT authors’ definition and in line with our inclusion criteria. Two independent researchers per article will conduct preliminary title and abstract screening, subsequent full text review, and data extraction for the selected trials, with a third reviewer available to resolve conflicts. We will assess the quality of all included studies using specific criteria regarding data reporting, external validity, and internal validity. We will combine all selected studies and conduct a narrative synthesis to assess enrollment metrics. If there is sufficient homogeneity and sufficient trials comparing recruitment strategies within disadvantaged populations, we will conduct a random effects meta-analysis to evaluate the effectiveness of strategies designed to maximize the inclusion of disadvantaged populations in randomized controlled trials. Discussion The findings of this systematic review will establish baseline recruitment and enrollment metrics of trials targeting disadvantaged populations to elucidate the scope of the challenge of recruiting such populations. We hope that our findings will promote future research on the distinct barriers that may prevent disadvantaged populations from participating in health intervention research, will encourage more trials exploring effective, tailored recruitment strategies, and will establish a foundation to track future progress in the recruitment of disadvantaged populations. Trial registrations PROSPERO ID: CRD42020152814

Hyperbaric Oxygen Therapy and Late Local Toxic Effects in Patients With Irradiated Breast Cancer

“…In total, 189 of 317 cohort participants (59.6%) with late toxic effects were eligible for this trial and randomized into HONEY. This proportion is much higher than the proportion of eligible patients usually randomized into classic RCTs, particularly RCTs involving HBOT . As observed in previous trials, the TWICS approach proved to be rather efficient, as 189 participants were enrolled in a single institution within 22 months, despite interruption of study recruitment due to COVID-19 lockdowns …”

Recruitment and Retention Strategies for Parents Experiencing Vulnerability: Lessons from an Online Parenting Program

“…Of these, four (6%) families were ineligible (i.e., child was not 3–36 months of age), three (4%) were not reachable with up to 10 contact attempts, eight (12%) declined, and four (6%) consented but did not start ( n = 3) or complete ( n = 1) the first appointment. As a result, 48 families from community agencies participated, resulting in recruitment (i.e., percentage enrolled out of those assessed for eligibility) and enrollment (percentage enrolled out of eligible dyads) rates (LaPlante et al, 2021) of 75% and 80%, respectively. To ascertain eligibility, on average, we attempted (i.e., telephone call, text, email) to reach families 2.91 ( SD = 2.16, range = 1–10) times.…”

National, regional, and urban-rural patterns in fixed-terrestrial broadband internet access and cardiac rehabilitation utilization in the United States

“…Additionally, if CMS first requires large-scale randomized clinical trial evidence to endorse the clinical benefits of telehealth CR as an option for standard of care, acquiring such data in a representative patient cohort of diverse social and economic backgrounds could prove extremely challenging and biased without universal fixed-terrestrial broadband internet access already in-place. Equitable representation of patients exhibiting characteristics predictive of low socioeconomic status in randomized clinical trials is rare and an ongoing concern for the development of medical treatments and improving access to preventive healthcare [31] , [32] , [33] .…”