What are effective methods to recruit research participants into mental health trials?

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Abstract

Background: There is a great need for effective treatments for mental health problems. Randomised controlled trials are the gold standard for evaluating treatments, however recruitment into trials is challenging, highlighting a clear need for evidence-based recruitment strategies. This thesis aimed to systematically develop a recruitment intervention and evaluate its effectiveness for improving the recruitment of participants into mental health trials.Methods: A mixed-methods approach, adopting the Medical Research Council’s complex interventions framework: 1) a systematic review to identify the evidence base and describe the factors affecting recruitment into depression trials; 2) a qualitative study to understand patients’ decision-making process in declining to enrol in a depression trial; 3) development of a recruitment intervention, using Participatory Design methods; and 4) evaluation of the recruitment intervention, using a randomised controlled trial, embedded in an ongoing mental health trial (the EQUIP trial). The primary outcome was the proportion of participants enrolled in EQUIP. Results: From the systematic review, a conceptual framework of factors influencing the decision to participate was developed, which highlighted that the decision to enrol involves a judgement between risk and reward. Findings suggested that patient and public involvement in research (PPIR) might be advertised to potential participants to reduce such perceived risk. The qualitative study found positive views of trials. Interviewees’ decision making resembled a four-stage process; in each stage they either decided to decline or progressed to the next stage. In Stage 1, those with an established position of declining trials opted out – they are termed ‘prior decliners’. In Stage 2, those who opted out after judging themselves ineligible are termed ‘self-excluders’. In Stage 3, those who decided they did not need the trial therapy and opted out are termed ‘treatment decliners’. In Stage 4, those who opted out after judging that disadvantages outweighed advantages are termed ‘trial decliners’. While ‘prior decliners’ are unlikely to respond to trial recruitment initiatives, the factors leading others to decline are amenable to amelioration as they do not arise from a rejection of trials. We recruited a host mental health trial (EQUIP), and worked with key stakeholders, including mental health service users and carers, to develop an intervention using a leaflet to advertise the nature and function of the PPIR in EQUIP to potential trial participants. 34 community mental health teams were randomised and 8182 patients invited. For the primary outcome, 4% of patients in the PPIR group were enrolled versus 5.3% of the control group. The intervention was not effective for improving recruitment rates (adjusted OR= 0.75, 95% CI= 0.53 to 1.07, p=0.113). Conclusions: This thesis reports the largest ever trial to evaluate the impact of a recruitment intervention. It also reports the largest trial of a PPIR intervention and makes a contribution to the evidence base on trial recruitment as well as to that assessing the impact of PPIR. Two further embedded trials are underway to evaluate the effectiveness of different versions of the recruitment intervention in different trial contexts and patient populations. This will also allow the results to be pooled to generate a more precise estimate of effect; to evaluate the impact of the intervention on trial retention; and to explore patient experiences of receiving the intervention.

Layman's Abstract

Why was the research in this thesis done?There is a need for better treatments to help people with mental health problems, but recruiting patients into randomised controlled trials to test new mental health treatments is very difficult. More effective recruitment strategies are urgently needed. This thesis aimed to develop and test a strategy for recruiting patients into mental health trials. What was done?The Medical Research Council’s ‘Framework for Developing Complex Interventions’ was used to: 1. Review the literature in a systematic way to find out about the factors that affect recruitment into trials recruiting people with depression 2. Speak with people who chose to not take part in a depression trial to understand their reasons as well as how they went about making their decision3. Develop a new strategy for recruiting patients, by working together with patients, carers and other key people4. Test this strategy using a real trial which aimed to recruit people with mental health problems. Patients invited into a mental health trial were randomly sent the new strategy or not. Findings compared how many people who did or did not get the new strategy actually took part in the trial What did the thesis find?The results of these studies found patients and doctors make a judgement between ‘risk and reward’ before deciding whether to take part in a trial. Most people who chose to not take part in a trial were positive about trials, but did not enrol because they felt they did not need the trial treatment. People who declined fell into different ‘types’; however most were likely to consider taking part in future trials. We developed and tested a strategy for recruiting patients, which was to directly tell people being asked to take part in a trial about the patient and public involvement that had already taken place in that trial, using a leaflet. We hoped that people learning about the patient and public involvement might see the trial as less ‘risky’. Findings showed that sending a leaflet about patient and public involvement was not effective as it did not increase the numbers of people actually taking part in the trial. What difference does this thesis make?This thesis adds to our understanding of how people make the decision to decline trials; to our understanding of what does and does not work for improving recruitment; and to understanding the impact of patient and public involvement. Further research building on this work is now underway.

Keyword(s)

Complex interventions framework; Mental health; Mesh: embedded trial; Meta-synthesis; Mixed methods; Participant recruitment; Patient and public involvement; Qualitative study; Randomised controlled trial; Research methodology; Service user involvement ; Study within a trial; systematic review

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