Dataset Information

Recruitment, consent and retention of participants in randomised controlled trials: a review of trials published in the National Institute for Health Research (NIHR) Journals Library (1997-2020).

ABSTRACT:

Objectives

To review the consent, recruitment and retention rates for randomised controlled trials (RCTs) funded by the UK's National Institute for Health Research (NIHR) and published in the online NIHR Journals Library between January 1997 and December 2020.

Design

Comprehensive review.

Setting

RCTs funded by the NIHR and published in the NIHR Journals Library.

Data extraction

Information relating to the trial characteristics, sample size, recruitment and retention.

Primary and secondary outcome measures

The primary outcome was the recruitment rate (number of participants recruited per centre per month). Secondary outcomes were the target sample size and whether it was achieved; consent rates (percentage of eligible participants who consented and were randomised) and retention rates (percentage of randomised participants retained and assessed with valid primary outcome data).

Results

This review identified 388 individual RCTs from 379 reports in the NIHR Journals Library. The final recruitment target sample size was achieved in 63% (245/388) of the RCTs. The original recruitment target was revised in 30% (118/388) of trials (downwards in 67% (79/118)). The median recruitment rate (participants per centre per month) was found to be 0.95 (IQR: 0.42-2.60); the median consent rate was 72% (IQR: 50%-88%) and the median retention rate was estimated at 88% (IQR: 80%-97%).

Conclusions

There is considerable variation in the consent, recruitment and retention rates in publicly funded RCTs. Although the majority of (6 out of 10) trials in this review achieved their final target sample; 3 out of 10 trials revised their original target sample size (downwards in 7 out of 10 trials). Investigators should bear this in mind at the planning stage of their study and not be overly optimistic about their recruitment projections.

SUBMITTER: Jacques RM

PROVIDER: S-EPMC8845327 | biostudies-literature | 2022 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Recruitment, consent and retention of participants in randomised controlled trials: a review of trials published in the National Institute for Health Research (NIHR) Journals Library (1997-2020).

Jacques Richard M RM Ahmed Rashida R Harper James J Ranjan Adya A Saeed Isra I Simpson Rebecca M RM Walters Stephen J SJ

BMJ open 20220214 2

<h4>Objectives</h4>To review the consent, recruitment and retention rates for randomised controlled trials (RCTs) funded by the UK's National Institute for Health Research (NIHR) and published in the online NIHR Journals Library between January 1997 and December 2020.<h4>Design</h4>Comprehensive review.<h4>Setting</h4>RCTs funded by the NIHR and published in the NIHR Journals Library.<h4>Data extraction</h4>Information relating to the trial characteristics, sample size, recruitment and retention ...[more]

PMID: 35165116

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Project description:BackgroundIn cluster randomised controlled trials (cRCTs), groups of individuals (rather than individuals) are randomised to minimise the risk of contamination and/or efficiently use limited resources or solve logistic and administrative problems. A major concern in the primary analysis of cRCT is the use of appropriate statistical methods to account for correlation among outcomes from a particular group/cluster. This review aimed to investigate the statistical methods used in practice for analysing the primary outcomes in publicly funded cluster randomised controlled trials, adherence to the CONSORT (Consolidated Standards of Reporting Trials) reporting guidelines for cRCTs and the recruitment abilities of the cluster trials design.MethodsWe manually searched the United Kingdom's National Institute for Health Research (NIHR) online Journals Library, from 1 January 1997 to 15 July 2021 chronologically for reports of cRCTs. Information on the statistical methods used in the primary analyses was extracted. One reviewer conducted the search and extraction while the two other independent reviewers supervised and validated 25% of the total trials reviewed.ResultsA total of 1942 reports, published online in the NIHR Journals Library were screened for eligibility, 118 reports of cRCTs met the initial inclusion criteria, of these 79 reports containing the results of 86 trials with 100 primary outcomes analysed were finally included. Two primary outcomes were analysed at the cluster-level using a generalized linear model. At the individual-level, the generalized linear mixed model was the most used statistical method (80%, 80/100), followed by regression with robust standard errors (7%) then generalized estimating equations (6%). Ninety-five percent (95/100) of the primary outcomes in the trials were analysed with appropriate statistical methods that accounted for clustering while 5% were not. The mean observed intracluster correlation coefficient (ICC) was 0.06 (SD, 0.12; range, - 0.02 to 0.63), and the median value was 0.02 (IQR, 0.001-0.060), although 42% of the observed ICCs for the analysed primary outcomes were not reported.ConclusionsIn practice, most of the publicly funded cluster trials adjusted for clustering using appropriate statistical method(s), with most of the primary analyses done at the individual level using generalized linear mixed models. However, the inadequate analysis and poor reporting of cluster trials published in the UK is still happening in recent times, despite the availability of the CONSORT reporting guidelines for cluster trials published over a decade ago.

Project description:BackgroundThe approximately 1100 medical journals now active in China are publishing a rapidly increasing number of research reports, including many studies identified by their authors as randomized controlled trials. It has been noticed that these reports mostly present positive results, and their quality and authenticity have consequently been called into question. We investigated the adequacy of randomization of clinical trials published in recent years in China to determine how many of them met acceptable standards for allocating participants to treatment groups.MethodsThe China National Knowledge Infrastructure electronic database was searched for reports of randomized controlled trials on 20 common diseases published from January 1994 to June 2005. From this sample, a subset of trials that appeared to have used randomization methods was selected. Twenty-one investigators trained in the relevant knowledge, communication skills and quality control issues interviewed the original authors of these trials about the participant randomization methods and related quality-control features of their trials.ResultsFrom an initial sample of 37,313 articles identified in the China National Knowledge Infrastructure database, we found 3137 apparent randomized controlled trials. Of these, 1452 were studies of conventional medicine (published in 411 journals) and 1685 were studies of traditional Chinese medicine (published in 352 journals). Interviews with the authors of 2235 of these reports revealed that only 207 studies adhered to accepted methodology for randomization and could on those grounds be deemed authentic randomized controlled trials (6.8%, 95% confidence interval 5.9-7.7). There was no statistically significant difference in the rate of authenticity between randomized controlled trials of traditional interventions and those of conventional interventions. Randomized controlled trials conducted at hospitals affiliated to medical universities were more likely to be authentic than trials conducted at level 3 and level 2 hospitals (relative risk 1.58, 95% confidence interval 1.18-2.13, and relative risk 14.42, 95% confidence interval 9.40-22.10, respectively). The likelihood of authenticity was higher in level 3 hospitals than in level 2 hospitals (relative risk 9.32, 95% confidence interval 5.83-14.89). All randomized controlled trials of pre-market drug clinical trial were authentic by our criteria. Of the trials conducted at university-affiliated hospitals, 56.3% were authentic (95% confidence interval 32.0-81.0).ConclusionMost reports of randomized controlled trials published in some Chinese journals lacked an adequate description of randomization. Similarly, most so called 'randomized controlled trials' were not real randomized controlled trials owing to a lack of adequate understanding on the part of the authors of rigorous clinical trial design. All randomized controlled trials of pre-market drug clinical trial included in this research were authentic. Randomized controlled trials conducted by authors in high level hospitals, especially in hospitals affiliated to medical universities had a higher rate of authenticity. That so many non-randomized controlled trials were published as randomized controlled trials reflected the fact that peer review needs to be improved and a good practice guide for peer review including how to identify the authenticity of the study urgently needs to be developed.

Project description:Objectives (1) To assess endorsement of trial registration in author instructions of urology-related journals and (2) to assess whether randomised controlled trials (RCTs) in the field of urology were effectively registered. Design Cross-sectional study of author instructions and published trials. Setting Journals publishing in the field of urology. Participants First, the authors analysed author instructions of 55 urology-related journals indexed in 'Journal Citation Reports 2009' (12/2010). The authors divided these journals in two groups: those requiring and those not mentioning trial registration as a precondition for publication. Second, the authors chose the five journals with the highest impact factor (IF) from each group. Intervention MEDLINE search to identify RCTs published in these 10 journals in 2009 (01/2011); search of the clinical trials meta-search interface of WHO (International Clinical Trials Registry Platform) for RCTs that lacked information about registration (01-03/2011). Two authors independently assessed the information. Outcome measures Proportion of journals providing advice about trial registration and proportion of trials registered. Results Of 55 journals analysed, 26 (47.3%) provided some editorial advice about trial registration. Journals with higher IFs were more likely to mention trial registration explicitly (p=0.015). Of 106 RCTs published in 2009, 63 were registered (59.4%) with a tendency to an increase after 2005 (83.3%, p=0.035). 71.4% (30/42) of the RCTs that were published in journals mentioning and requiring registration, and 51.6% (33/64) of the RCTs that were published in journals that did not mention trial registration explicitly were registered. This difference was statistically significant (p=0.04). Conclusions The existence of a statement about trial registration in author instructions resulted in a higher proportion of registered RCTs in those journals. Journals with higher IFs were more likely to mention trial registration.

Project description:Background and aimThe recruitment process in a randomized trial can be challenging. Poor recruitment can have a negative impact on the allocated budget and estimated completion date of the study and may result in an underpowered study. We aimed to perform a Study Within A Trial (SWAT) to evaluate the impact of same-day consent or delayed consent on recruitment and retention in the host trial.MethodsThis SWAT is designed as a prospective cohort design. The host trial was a randomized controlled trial evaluating the effectiveness of an intensive lifestyle modification programme in participants with peripheral arterial disease. Researchers screened the participants for inclusion and exclusion criteria. Informed consents were obtained from the participants who were willing to participate in the study on a standardized consent form. Participants were given the option to consent on the same day or to delay their consent. Following the consent, the participants were allocated to two groups (same-day consent vs. delayed consent) based on pre-determined criteria for SWAT. One hundred sixteen participants were consented to take part in the host trial. Seventy-five participants were randomized to the host trial. The primary outcome was the proportion of participants who withdrew consent at the recruitment phase. Secondary outcomes were reasons for consent withdrawal and dropout, attrition rate, and adherence with the host trial intervention.ResultsThere was a significantly lower consent-withdrawal rate in same-day consent (17.4%, n = 8/46), compared to the delayed consent group (47.1%, n = 33/70), p = 0.001. There was a significantly lower dropout rate in participants randomized following same-day consent (10.5%, n = 4/38), compared to those randomized after delayed consent (29.7%, n = 11/37), p = 0.038. Transport was the main reason mentioned for consent withdrawal and dropout. In participants randomized to the host trial intervention arm, there was a significant difference in adherence (percentage of the 12-week programme completed) between same-day consent (96.7% ± 4.9) and delayed consent participants (86.4% ± 11.2), p = 0.003, as well as number of weeks completed (mean difference = - 1.547, 95% confidence intervals (- 2.237 to - 0.85)), p = 0.02.ConclusionThis SWAT found evidence that participants who gave consent on the same day seemed to have better adherence and fewer-withdrawal and dropout rates.Swat registrationThe SWAT was registered on the Northern Ireland Network for Trials Methodology Research, SWAT 84.

Project description:Cognitive impairment is a characteristic of schizophrenia. This impairment may affect the retention of information required for ongoing knowledgeable participation in clinical trials. This study monitored retention of study-related knowledge-including assessment of therapeutic misconception-in people with stable, DSM-IV schizophrenia during participation in placebo-controlled clinical trials of adjunctive agents. Stability was defined as being on an antipsychotic with no change in medication or dose over the previous 4 weeks.This longitudinal study assessed retention of clinical trial-related consent information. Individuals enrolling in 1 of 8 clinical trials were approached for participation. Participants came from research clinics and community mental health centers. At baseline, clinical trial consent forms were reviewed and study knowledge assessed. Participants were randomized to follow-up assessments at weeks 1, 4, and 8; weeks 4 and 8; or at week 8 only. Clinical trial consent forms were not rereviewed at any follow-up visit.Fifty-nine participants were enrolled; analysis included 52 participants with at least 1 follow-up visit. Study knowledge did not decrease meaningfully in any group. Therapeutic misconception was not observed in participants during the study. The group assessed most frequently demonstrated significant improvement over baseline (t44 = 3.43, P = .001). Retention of study knowledge was not related to symptoms but had a weak correlation with cognitive capacity (R = 0.28, P = .07). Performance did not differ between participants from research clinics and those from community mental health centers.Clinically stable people with schizophrenia enrolling in a placebo-controlled adjunctive medication study, once determined to have capacity to consent to a clinical trial, retained appropriate study knowledge for at least 8 weeks. In the absence of a specific reason to suspect a loss of decisional capacity, there appears to be no need to routinely reevaluate participants during this type of clinical trial.

Project description:Importance:Multiple analyses in a clinical trial can increase the probability of inaccurately concluding that there is a statistically significant treatment effect. However, to date, it is unknown how many randomized clinical trials (RCTs) perform adjustments for multiple comparisons, the lack of which could lead to erroneous findings. Objectives:To assess the prevalence of multiplicity and whether appropriate multiplicity adjustments were performed among cardiovascular RCTs published in 6 medical journals with a high impact factor. Design, Setting, and Participants:In this cross-sectional study, cardiovascular RCTs were selected from all over the world, characterized as North America, Western Europe, multiregional, and rest of the world. Data were collected from past issues of 3 cardiovascular journals (Circulation, European Heart Journal, and Journal of the American College of Cardiology) and 3 general medicine journals (JAMA, The Lancet, and The New England Journal of Medicine) with high impact factors published between August 1, 2015, and July 31, 2018. Supplements and trial protocols of each of the included RCTs were also searched for multiplicity. Data were analyzed December 20 to 27, 2018. Exposures:Data from the selected RCTs were extracted and verified independently by 2 researchers using a structured data instrument. In case of disagreement, a third reviewer helped to achieve consensus. An RCT was considered to have multiple treatment groups if it had more than 2 arms; multiple outcomes were defined as having more than 1 primary outcome, and multiple analyses were defined as analysis of the same outcome variable in multiple ways. Multiplicity was examined only for the analysis of the primary end point. Main Outcomes and Measures:Outcomes of interest were percentages of primary analyses that performed multiplicity adjustment of primary end points. Results:Of 511 cardiovascular RCTs included in this analysis, 300 (58.7%) had some form of multiplicity; of these 300, only 85 (28.3%) adjusted for multiplicity. Intervention type and funding source had no statistically significant association with the reporting of multiplicity risk adjustment. Trials that assessed mortality vs nonmortality outcomes were more likely to contain a multiplicity risk in their primary analysis (66.3% [177 of 267] vs 50.4% [123 of 244]; P?<?.001), and larger trials vs smaller trials were less likely to make any adjustments for multiplicity (35.6% [52 of 146] vs 21.4% [33 of 154]; P?=?.001). Conclusions and Relevance:Findings from this study suggest that cardiovascular RCTs published in medical journals with high impact factors demonstrate infrequent adjustments to correct for multiple comparisons in the primary end point. These parameters may be improved by more standardized reporting.

Dataset Information

Recruitment, consent and retention of participants in randomised controlled trials: a review of trials published in the National Institute for Health Research (NIHR) Journals Library (1997-2020).

Objectives

Design

Setting

Data extraction

Primary and secondary outcome measures

Results

Conclusions

Publications

Recruitment, consent and retention of participants in randomised controlled trials: a review of trials published in the National Institute for Health Research (NIHR) Journals Library (1997-2020).

Similar Datasets

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