Routinely embedding recruitment and retention interventions within randomised controlled trials

Lead Research Organisation: University of York
Department Name: Health Science


There is a need to improve health care and wellbeing by developing and testing new treatments. The best way to test these new treatments is using a randomised controlled trial (RCT). In a RCT some patients get the new treatment and some do not. The results of the different groups are then compared to see if the treatment leads to better health. Many trials like this are run in the NHS but recruiting patients and keeping them engaged in these trials is often very difficult and takes longer than planned. The methods used to approach people generally have not been tested to see if they work, meaning research teams don't know how best to recruit and keep patients engaged. Because of this, research is often delayed and patients and professionals cannot benefit from knowing which treatments work best.

Recently, there has been an interest in testing different ways of recruiting and keeping patients engaged in RCTs that are taking place in the NHS. The testing is done in studies set within a larger RCT. These studies are called 'Studies Within A Trial' or SWATs. The Medical Research Council previously funded members of our research team to find out whether it was possible to do SWATs across a range of different trials at the same time, and to design standards for doing them. With this funding we were able to design frameworks and standards for doing and reporting SWATs. Recently a database of SWATs has been set up. This database can be used by other researchers to share their ideas for SWATs and to encourage others to do these types of studies, so that findings might in future be combined to develop better evidence of what works.

Our aim is to build on this earlier work by making SWATs standard practice across Clinical Trials Units, which are the leading centres for doing RCTs in the UK. We would like to support at least 25 SWATs, by giving teams doing SWATs advice and financial support of £5000 to cover the costs of doing each SWAT. We have set up a network of Clinical Trials Units who have committed to starting at least two SWATs that are focused on recruiting and keeping patients engaged. The ultimate aim is to make SWATs routine when doing a clinical trial. This will help the NHS to do better research which will lead to knowledge of how to improve the health and well-being of patients.

Technical Summary

Many aspects of randomised controlled trials (RCTs) have, ironically, not been subjected to rigorous evaluation. In particular interventions to enhance recruitment and retention tend often to be based on 'custom and practice' rather than using approaches that have been tested using the most rigorous methodological approaches: particularly randomisation. However, there is an increasing interest in embedding methodological studies within randomised controlled trials. The MRC funded the START study, which aimed to test out two interventions for recruitment and retention across a number of clinical trials by performing 'Studies within a Trial' or SWATs and found it is feasible to undertake SWATs across a range of different trials and to undertake a pre-planned meta-analysis of their results. Furthermore, a SWATs Repository has been established with the aim of encouraging dissemination of SWAT ideas and their standardisation to facilitate future meta-analysis and synthesis. The aim of this programme of research is to build on the START initiative and make embedding 'Studies within a Trial' or SWATs as standard practice across multiple clinical trials units. We intend to pump prime and facilitate the start of at least 20 SWATs across multiple trials units within 30 months. We have established a network of trials units who have committed to starting at least two SWATs in the areas of recruitment and retention within 30 months of starting this study. The ultimate aim is to make the inclusion of SWATs routine when conducting a clinical trial.

Planned Impact

Worldwide, there is a desire to improve health and wealth through research. The National Institute for Health Research (NIHR) has outlined a vision which sees 'more patients and health professionals participating in health research'. Fundamental to health research is the testing of interventions through RCTs, which require active participation by patients and professionals. However, achieving that participation is difficult. Published data indicate that a minority of RCTs recruit successfully in terms of numbers and timeline, whilst a significant number of enrolled participants are not retained throughout the trial. Recruitment and retention problems impact on both the total sample (limiting power and internal validity), and the proportion of eligible participants recruited and retained (limiting external validity). The impact of research is reduced if evidence is delayed or its rigour and generalisability compromised. Significant resources have been invested in networks to support delivery of RCTs and other research, which has had a significant impact. However, investment in networks and the development of recruitment and retention models have not generally been based on rigorous evidence, and many challenges remain. A robust test of the effectiveness of a particular recruitment or retention method is an RCT comparing one method with an alternative, a study embedded within an ongoing 'host' trial or a Study Within A Trial (SWAT). Systematic reviews have identified only a small number of such studies, and their size, scope and restriction to single trials severely limited their utility and generalisability. The proposed project will utilise existing methodological frameworks and protocols to routinely test recruitment and retention interventions across multiple 'host' RCTs.

At the completion of this programme, we will have rigorously evaluated recruitment and retention interventions across at least 25 trials, and introduced the adoption of SWATs as a routine part of research practice within our collaborating trials units. In the medium term, we will have provided the basis for the routine delivery of recruitment and retention SWATs. This will facilitate the rapid development of an evidence base to improve recruitment outcomes (such as time to recruitment, proportion of eligible patients recruited and retained, cost per patient recruited and retained and participation among marginalised groups) across trials in the public and commercial sector, and in all settings. In the long-term, we aim to provide a significant platform to help NIHR achieve its goals of 'more patients and health professionals participating in health research', which will in turn make an enduring contribution to the health and wealth of the United Kingdom and elsewhere.


10 25 50

Description Impact on implementing SWATs in NIHR trials
Geographic Reach National 
Policy Influence Type Implementation circular/rapid advice/letter to e.g. Ministry of Health