Non-randomised evaluations of strategies to increase participant retention in randomised controlled trials: a systematic review
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ABSTRACT:
SUBMITTER: Elfeky A
PROVIDER: S-EPMC7523052 | biostudies-literature | 2020 Jan
REPOSITORIES: biostudies-literature
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Project description:Randomised control trials are regarded as the gold standard for evaluating the effectiveness and efficacy of healthcare interventions with thousands of trials published every year. Despite significant investment in infrastructure, a staggering number of clinical trials continue to face challenges with retention. Dropouts could lead to negative consequences-from lengthy delays to missing data that can undermine the results and integrity of the trial. Summarising evidence from non-randomised evaluations of retention strategies could provide complementary information to randomised evaluations that could guide trialists to the most effective ways of increasing retention of participants in clinical trials.The following electronic databases will be searched for relevant studies: EMBASE, MEDLINE, the Cochrane Controlled Trials Register, and Cochrane Methodology Register and the search will be limited to English-published studies during the last 10 years to increase relevance to current trials. Non-randomised studies (observational studies) including a comparison of two or more strategies to increase participant retention in randomised trials or comparing one or more strategies with no strategy will be included. The primary outcome will be the proportion of participants remained at the primary analysis as determined in each retention study.This review aims to gather and evaluate evidence on the effect of retention strategies examined in non-randomised studies. It is imperative to collect evidence from obseravational studies to infer whether or not these studies could be considered a practical way to complement or even replace a broadly favourable randomised design. If we find that non-randomised studies to be included in this review are of high quality with adequate control of biases, we will recommend to trialists and others not to rely exclusively on randomised studies and to give meticulous attention to the plentiful evidence that can be obtained from non-randomised studies. Should the results of this review suggest that evaluating retention strategies in observational studies provides insufficient evidence to trialists planning their retention strategies, we will be able to say that there is little point in conducting non-randomised studies and that they would do better to invest their time and resources in a randomised evaluation if possible. Where a non-randomised study design is chosen, the review authors will offer recommendations to trialists and others regarding how to ensure that these studies are conducted in a way that can minimise the risk of bias and increase confidence in the findings.PROSPERO 2017: CRD42017072775 .
| S-EPMC5819085 | biostudies-other
Project description:Search strategies for systematic reviews aim to identify all evidence relevant to the research question posed. Reports of methodological research can be difficult to find leading to biased results in systematic reviews of research methodology. Evidence suggests that contact with investigators can help to identify unpublished research. To identify additional eligible randomised controlled trials (RCTs) for a Cochrane systematic review of strategies to improve retention in RCTs, we conducted a survey of UK clinical trials units (CTUs) and made contact with RCT methodologists.Key contacts for all UK CTUs were sent a personalised email with a short questionnaire and summary protocol of the Cochrane methodology review. The questionnaire asked whether a RCT evaluating strategies to improve retention embedded in a RCT had ever been conducted by the CTU. Questions about the stage of completion and publication of such RCTs were included. The summary protocol outlined the aims, eligibility criteria, examples of types of retention strategies, and the primary outcome for the systematic review. Personal communication with RCT methodologists and presentations of preliminary results of the review at conferences were also used to identify additional eligible RCTs. We checked the results of our standard searches to see if eligible studies identified through these additional methods were also found using our standard searches.We identified 14 of the 38 RCTs included in the Cochrane methodology review by contacting trials units and methodologists. Eleven of the 14 RCTs identified by these methods were either published in grey literature, in press or unpublished. Three remaining RCTs were fully published at the time. Six of the RCTs identified were not found through any other searches. The RCTs identified represented data for 6 of 14 RCTs of incentive strategies (52% of randomised participants included in the review), and 6 of 14 RCTs of communication strategies (52% of randomised participants included in the Cochrane review). Data were unavailable for two of the RCTs identified.Methodological evaluations embedded in RCTs may be unpublished, published in the grey literature or where published, poorly indexed in bibliographic databases. To identify such studies and minimise selection bias in systematic reviews of methodological evaluations, reviewers should consider contacting CTUs and trial methodologists.
| S-EPMC5568351 | biostudies-other
Project description:BackgroundRecruitment of participants into randomised controlled trials (RCTs) is critical for successful trial conduct. Although there have been two previous systematic reviews on related topics, the results (which identified specific interventions) were inconclusive and not generalizable. The aim of our study was to evaluate the relative effectiveness of recruitment strategies for participation in RCTs.Methods and findingsA systematic review, using the PRISMA guideline for reporting of systematic reviews, that compared methods of recruiting individual study participants into an actual or mock RCT were included. We searched MEDLINE, Embase, The Cochrane Library, and reference lists of relevant studies. From over 16,000 titles or abstracts reviewed, 396 papers were retrieved and 37 studies were included, in which 18,812 of at least 59,354 people approached agreed to participate in a clinical RCT. Recruitment strategies were broadly divided into four groups: novel trial designs (eight studies), recruiter differences (eight studies), incentives (two studies), and provision of trial information (19 studies). Strategies that increased people's awareness of the health problem being studied (e.g., an interactive computer program [relative risk (RR) 1.48, 95% confidence interval (CI) 1.00-2.18], attendance at an education session [RR 1.14, 95% CI 1.01-1.28], addition of a health questionnaire [RR 1.37, 95% CI 1.14-1.66]), or a video about the health condition (RR 1.75, 95% CI 1.11-2.74), and also monetary incentives (RR1.39, 95% CI 1.13-1.64 to RR 1.53, 95% CI 1.28-1.84) improved recruitment. Increasing patients' understanding of the trial process, recruiter differences, and various methods of randomisation and consent design did not show a difference in recruitment. Consent rates were also higher for nonblinded trial design, but differential loss to follow up between groups may jeopardise the study findings. The study's main limitation was the necessity of modifying the search strategy with subsequent search updates because of changes in MEDLINE definitions. The abstracts of previous versions of this systematic review were published in 2002 and 2007.ConclusionRecruitment strategies that focus on increasing potential participants' awareness of the health problem being studied, its potential impact on their health, and their engagement in the learning process appeared to increase recruitment to clinical studies. Further trials of recruitment strategies that target engaging participants to increase their awareness of the health problems being studied and the potential impact on their health may confirm this hypothesis. Please see later in the article for the Editors' Summary.
| S-EPMC2976724 | biostudies-literature
Project description:ObjectiveTo quantify the effect of strategies to improve retention in randomised trials.DesignSystematic review and meta-analysis.Data sourcesSources searched: MEDLINE, EMBASE, PsycINFO, DARE, CENTRAL, CINAHL, C2-SPECTR, ERIC, PreMEDLINE, Cochrane Methodology Register, Current Controlled Trials metaRegister, WHO trials platform, Society for Clinical Trials (SCT) conference proceedings and a survey of all UK clinical trial research units.Review methodsIncluded trials were randomised evaluations of strategies to improve retention embedded within host randomised trials. The primary outcome was retention of trial participants. Data from trials were pooled using the fixed-effect model. Subgroup analyses were used to explore the heterogeneity and to determine whether there were any differences in effect by the type of strategy.Results38 retention trials were identified. Six broad types of strategies were evaluated. Strategies that increased postal questionnaire responses were: adding, that is, giving a monetary incentive (RR 1.18; 95% CI 1.09 to 1.28) and higher valued incentives (RR 1.12; 95% CI 1.04 to 1.22). Offering a monetary incentive, that is, an incentive given on receipt of a completed questionnaire, also increased electronic questionnaire response (RR 1.25; 95% CI 1.14 to 1.38). The evidence for shorter questionnaires (RR 1.04; 95% CI 1.00 to 1.08) and questionnaires relevant to the disease/condition (RR 1.07; 95% CI 1.01 to 1.14) is less clear. On the basis of the results of single trials, the following strategies appeared effective at increasing questionnaire response: recorded delivery of questionnaires (RR 2.08; 95% CI 1.11 to 3.87); a 'package' of postal communication strategies (RR 1.43; 95% CI 1.22 to 1.67) and an open trial design (RR 1.37; 95% CI 1.16 to 1.63). There is no good evidence that the following strategies impact on trial response/retention: adding a non-monetary incentive (RR=1.00; 95% CI 0.98 to 1.02); offering a non-monetary incentive (RR=0.99; 95% CI 0.95 to 1.03); 'enhanced' letters (RR=1.01; 95% CI 0.97 to 1.05); monetary incentives compared with offering prize draw entry (RR=1.04; 95% CI 0.91 to 1.19); priority postal delivery (RR=1.02; 95% CI 0.95 to 1.09); behavioural motivational strategies (RR=1.08; 95% CI 0.93 to 1.24); additional reminders to participants (RR=1.03; 95% CI 0.99 to 1.06) and questionnaire question order (RR=1.00, 0.97 to 1.02). Also based on single trials, these strategies do not appear effective: a telephone survey compared with a monetary incentive plus questionnaire (RR=1.08; 95% CI 0.94 to 1.24); offering a charity donation (RR=1.02, 95% CI 0.78 to 1.32); sending sites reminders (RR=0.96; 95% CI 0.83 to 1.11); sending questionnaires early (RR=1.10; 95% CI 0.96 to 1.26); longer and clearer questionnaires (RR=1.01, 0.95 to 1.07) and participant case management by trial assistants (RR=1.00; 95% CI 0.97 to 1.04).ConclusionsMost of the trials evaluated questionnaire response rather than ways to improve participants return to site for follow-up. Monetary incentives and offers of monetary incentives increase postal and electronic questionnaire response. Some strategies need further evaluation. Application of these results would depend on trial context and follow-up procedures.
| S-EPMC3918995 | biostudies-literature
Project description:BackgroundNon-retention of participants seriously affects the credibility of clinical trial results and significantly reduces the potential of a trial to influence clinical practice. Non-retention can be defined as instances where participants leave the study prematurely. Examples include withdrawal of consent and loss to follow-up and thus outcome data cannot be obtained. The majority of existing interventions targeting retention fail to describe any theoretical basis for the observed improvement, or lack of improvement. Moreover, most of these interventions lack involvement of participants in their conception and/or design, raising questions about their relevance and acceptability. Many of the causes of non-retention involve people performing a behaviour (e.g. not returning a questionnaire). Behaviour change is difficult, and the importance of a strong theoretical basis for interventions that aim to change behaviour is increasingly recognised. This research aims to develop and pilot theoretically informed, participant-centred, evidence-based behaviour change interventions to improve retention in trials.MethodsThis research will generate data through semi-structured interviews on stakeholders' perspectives of the reasons for trial non-retention. It will identify perceived barriers and enablers to trial retention using the Theoretical Domains Framework. The intervention development work will involve identification of behaviour change techniques, using recognised methodology, and co-production of retention interventions through discussion groups with end-users. An evaluation of intervention acceptability and feasibility will be conducted in focus groups. Finally, a ready-to-use evaluation framework to deploy in Studies Within A Trial as well as an explanatory retention framework will be developed for identifying and tackling modifiable issues to improve trial retention.DiscussionWe believe this to be one of the first studies to apply a theoretical lens to the development of interventions to improve trial retention that have been informed by, and are embedded within, participants' experiential accounts. By developing and identifying priority interventions this study will support efforts to reduce research waste.
| S-EPMC5869766 | biostudies-literature
Project description:BackgroundMany 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.MethodsWe 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.DiscussionThe 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 registrationsPROSPERO ID: CRD42020152814.
| S-EPMC8372683 | biostudies-literature
Project description:BackgroundRecruiting and retaining participants in randomised controlled trials (RCTs) is challenging. Digital tools, such as social media, data mining, email or text-messaging, could improve recruitment or retention, but an overview of this research area is lacking. We aimed to systematically map the characteristics of digital recruitment and retention tools for RCTs, and the features of the comparative studies that have evaluated the effectiveness of these tools during the past 10 years.MethodsWe searched Medline, Embase, other databases, the Internet, and relevant web sites in July 2018 to identify comparative studies of digital tools for recruiting and/or retaining participants in health RCTs. Two reviewers independently screened references against protocol-specified eligibility criteria. Included studies were coded by one reviewer with 20% checked by a second reviewer, using pre-defined keywords to describe characteristics of the studies, populations and digital tools evaluated.ResultsWe identified 9163 potentially relevant references, of which 104 articles reporting 105 comparative studies were included in the systematic map. The number of published studies on digital tools has doubled in the past decade, but most studies evaluated digital tools for recruitment rather than retention. The key health areas investigated were health promotion, cancers, circulatory system diseases and mental health. Few studies focussed on minority or under-served populations, and most studies were observational. The most frequently-studied digital tools were social media, Internet sites, email and tv/radio for recruitment; and email and text-messaging for retention. One quarter of the studies measured efficiency (cost per recruited or retained participant) but few studies have evaluated people's attitudes towards the use of digital tools.ConclusionsThis systematic map highlights a number of evidence gaps and may help stakeholders to identify and prioritise further research needs. In particular, there is a need for rigorous research on the efficiency of the digital tools and their impact on RCT participants and investigators, perhaps as studies-within-a-trial (SWAT) research. There is also a need for research into how digital tools may improve participant retention in RCTs which is currently underrepresented relative to recruitment research.RegistrationNot registered; based on a pre-specified protocol, peer-reviewed by the project's Advisory Board.
| S-EPMC7273688 | biostudies-literature
Project description:Objective: To identify variables associated with retention (or dropout) in infertility clinical trials. Retention of subjects in randomized controlled clinical trials (RCTs) has received considerable attention, but there have been few consistent findings.Design: Secondary analysis of data from RCTs.Setting: Academic medical centers.Patient(s): Women with polycystic ovary syndrome (PCOS) or couples with unexplained infertility, aged 18-40 years.Intervention(s): This study is not an intervention study, but the patients in the original RCTs were treated with any or combination of metformin, clomiphene citrate (CC), letrozole, and gonadotropins.Main outcome measure(s): Successful retention versus dropout during the RCTs.Result(s): Race, ethnicity, body mass index (BMI), insurance coverage, history of smoking, and history of alcohol use were significantly associated with retention whether they were considered in bivariate analyses or a multivariable logistic model. Specifically, white race, higher income, having graduate degrees, normal weight, better insurance coverage, nonsmokers, and those who reported current use of alcohol at the start of the trial, had higher retention rates.Conclusion(s): We identified several additive and persistent predictors of retention that can be used to guide the conduct of RCTs and improve the retention rate. Given the limitation of our association analysis, methodologically sound and theoretically grounded research are warranted so that high quality data can be collected to improve our understanding on the causes of dropout.Clinical trial registration number: NCT00068861 (PPCOS-I), NCT00719186 (PPCOS-II), and NCT01044862 (AMIGOS).
| S-EPMC4630082 | biostudies-literature
Project description:BACKGROUND:Recruitment and retention challenges are very common in mental health randomised trials. Investigators utilise different methods to improve recruitment or retention. However, evidence of the effectiveness and efficiency of these strategies in mental health has not been synthesised. This systematic review is to investigate and assess the effectiveness and cost-effectiveness of different strategies to improve recruitment and retention in mental health randomised trials. METHODS AND MATERIALS:MEDLINE, EMBASE, the Cochrane Methodology Register and PsycINFO were searched from beginning of record up to July 2016. Randomised trials involving participants with mental health problems which compared different strategies for recruitment or retention were selected. Two authors independently screened identified studies for eligibility. RESULTS:A total of 5,157 citations were identified. Thirteen articles were included, 11 on recruitment and 2 on retention. Three randomised controlled trials compared different recruitment strategies, none of which found statistically significant differences between the interventional recruitment strategies and the routine recruitment methods. Retrospective comparisons of recruitment methods showed that non-web-based advertisement and recruitment by clinical research staff each have advantages in efficiency. Web-based adverts had the lowest cost per person recruited (£13.41 per person recruited). Specialised care referral cost £183.24 per person, non-web-based adverts cost £372.03 per patient and recruitment via primary care cost £407.65 for each patient. Financial incentives, abridged questionnaires and pre-notification had a positive effect on retention rates. CONCLUSION:The recruitment studies included showed differences in strategies, clinical settings, mental health conditions and study design. It is difficult to assess the overall effectiveness of any particular recruitment strategy as some strategies that worked well for a particular population may not work as well for others. Paying attention to the accessibility of information and consent materials may help improve recruitment. More research in this area is needed given its important implications.
| S-EPMC6114918 | biostudies-literature
Project description:ObjectivesTo identify and review evaluations of strategies to recruit men aged 50 years and over to randomised controlled trials (RCTs).DesignSystematic review and narrative synthesis.Data sourcesMEDLINE, EMBASE, CINAHL and ORRCA databases were searched to 1 December 2017.Eligibility criteriaStudies using quantitative methods to evaluate recruitment strategies to RCTs of men aged 50 years and older.Data extraction and synthesisA single reviewer extracted data (for each strategy, number of participants approached, screened and randomised, and cost). Study quality was assessed using National Heart, Lung and Blood Institute Quality Assessment Tools and considered study design, description of interventions, description and measurement of outcomes, completeness of outcome reporting, performance of statistical testing and consideration of confounders. Recruitment strategies were categorised by the recruitment stage they addressed.ResultsSixteen studies (n >14?000) were included: one good quality, ten fair quality and five poor quality. Studies evaluated strategies to identify prospective participants, and to improve the processes for assessing participant eligibility, providing participant information and seeking consent. In good and fair quality studies, the most effective strategies for identifying participants were referral from an affiliated health service provider (two studies), mass mailing (five studies) and media coverage (two studies). Community outreach activities such as displaying posters and attending local community events were not effective (two studies). Trial-specific training of site recruitment staff, developed using qualitative analysis of recruitment visits (two studies), and provision of study information to prospective participants at a multidisciplinary, group information session (one study) both improved recruitment.ConclusionImproved engagement of men aged 50 years and older in RCTs is needed. A gender-sensitised approach to RCT recruitment may help to address this need. We have identified several promising recruitment strategies that merit further evaluation.Prospero registration numberCRD42017060301.
| S-EPMC6500287 | biostudies-literature