ReviewBMJ open2017
Recruitment and retention of participants in randomised controlled trials: a review of trials funded and published by the United Kingdom Health Technology Assessment Programme.
Review in BMJ open, 2017. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 321 papers, 13 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
321 citing papers in PubMed, 13 syntheses or guidelines pooled it.
- Strategies to improve recruitment to randomised trials.The Cochrane database of systematic reviews · 2026Pooled it
- Strategies for recruitment of adolescent girls into physical activity programmes: a systematic review and regression analysis.BMC public health · 2026Pooled it
- Pooled it
- Pooled it
- Factors that influence recruitment to COVID-19 vaccine trials: a qualitative evidence synthesis.Trials · 2024Pooled it
- Registry-based randomised controlled trials: conduct, advantages and challenges-a systematic review.Trials · 2024Pooled it
- Providing multimedia information to children and young people increases recruitment to trials: pre-planned meta-analysis of SWATs.BMC medicine · 2023Pooled it
- Pooled it
- Pooled it
- Recruitment and retention interventions in surgical and wound care trials: A systematic review.PloS one · 2023Pooled it
- Dropout Rate in Digital Health Interventions for the Prevention of Skin Cancer: Systematic Review, Meta-analysis, and Metaregression.Journal of medical Internet research · 2022Pooled it
- Recruiting and retaining young adults: what can we learn from behavioural interventions targeting nutrition, physical activity and/or obesity? A systematic review of the literature.Public health nutrition · 2021Pooled it
- Facilitators and barriers of children's participation in nutrition, physical activity, and obesity interventions: A systematic review.Obesity reviews : an official journal of the International Association for the Study of Obesity · 2021Pooled it
- Exploring a Facilitator-Enabled Flexible iSupport for Dementia Program: An Internal Pilot Mixed-Methods Study.Nursing open · 2026Trial
- Feasibility study of a novel mHealth clinical decision support application to enable community health workers to manage hypertension in rural Guatemala.Journal of global health · 2026Trial
- SWAT 116: the effectiveness of an infographic to improve trial recruitment-a randomised study within a trial (SWAT).Trials · 2026Trial
- WhatsApp-Supported Teledentistry to Reinforce Oral Health Promotion Among Older Adults Residing in Rural and Urban Areas: Randomized Controlled Trial.JMIR mHealth and uHealth · 2026Trial
- Trial
- Trial
- Implementing a patient-oriented pole walking intervention in retirement homes: A non-randomized feasibility trial.PloS one · 2026Trial
261 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
11 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundSubstantial amounts of public funds are invested in health research worldwide. Publicly funded randomised controlled trials (RCTs) often recruit participants at a slower than anticipated rate. Many trials fail to reach their planned sample size within the envisaged trial timescale and trial funding envelope.
objectivesTo review the consent, recruitment and retention rates for single and multicentre randomised control trials funded and published by the UK's National Institute for Health Research (NIHR) Health Technology Assessment (HTA) Programme. DATA SOURCES AND STUDY SELECTION: HTA reports of individually randomised single or multicentre RCTs published from the start of 2004 to the end of April 2016 were reviewed. DATA EXTRACTION: Information was extracted, relating to the trial characteristics, sample size, recruitment and retention by two independent reviewers.
main outcome measuresTarget sample size and whether it was achieved; recruitment rates (number of participants recruited per centre per month) and retention rates (randomised participants retained and assessed with valid primary outcome data).
resultsThis review identified 151 individually RCTs from 787 NIHR HTA reports. The final recruitment target sample size was achieved in 56% (85/151) of the RCTs and more than 80% of the final target sample size was achieved for 79% of the RCTs (119/151). The median recruitment rate (participants per centre per month) was found to be 0.92 (IQR 0.43-2.79) and the median retention rate (proportion of participants with valid primary outcome data at follow-up) was estimated at 89% (IQR 79-97%).
conclusionsThere is considerable variation in the consent, recruitment and retention rates in publicly funded RCTs. Investigators should bear this in mind at the planning stage of their study and not be overly optimistic about their recruitment projections.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.