Facing the challenges of recruitment to clinical trials

Posted on by Leslie Gelling in Ethics, informed consent, Recruitment and retention, Research

A huge amount of planning goes into writing research protocols and developing recruitment strategies but it is only when research begins in the real world that researchers can start to grapple with the challenges of recruitment.  During a recent Clinfield course on ‘Meeting the challenges of recruitment and retention in clinical research’ attendees were asked to draw on their experiences to highlight what they believed to be the main challenges when recruiting to clinical research (see below summary of issues raised).


From this long list of issues there were three that emerged as being challenges frequently encountered when recruiting to clinical research, including the logistics of recruiting in busy clinical settings, maintaining high quality recruitment practices whilst seeking to meet recruitment targets and inclusion and exclusion criteria that seek to recruit only perfect study participants.

Recruiting in busy clinical settings

Recruitment to clinical research often happens in busy clinical settings where patients and clinicians have much more to consider than the possibility of engaging with clinical research.  Patients might be undergoing a number of investigative or therapeutic procedures at a time of great anxiety to them and to their families.  There is always a danger that asking someone if they would be willing to participate in clinical research at this time could add to the patient’s existing burden.  It might help if potential research participants could be primed to expect a conversation about being involved in research.  At a personal level, they could be sent information about the proposed research in the weeks before the next clinic apportionment or planned hospital admission.  On a wider level, efforts could be made to make patients aware that the hospital or clinic they are attending is research active and that patients should expect to be approached about participating in clinical research?  A combination of these strategies would help to make conversations about participating in clinical research easier for all involved.

Meeting inclusion and exclusion criteria

Whilst it is important to have inclusion and exclusion criteria, greater consideration should be given to minimising the limiting consequences of seeking to meet these criteria.  Are they all necessary?  Might expanding these criteria make it easier to recruit and possibly create a study population that more usefully reflects the patient population that might eventually use the medication being studied?  During the most recent Clinfield course it was interesting to hear one attendee describe how they were currently screen approximately 300 patients to recruit a single participant.  There wasn’t time to debate how that single participant might be representative, or not, of the 299 who failed screening.

Maintaining high quality recruitment practices

Even when potential participants meet inclusion criteria, it is still unrealistic to expect that everyone invited to participate in a clinical trial will give their informed consent.  There will be many legitimate reasons for this but it is important to remember that seeking to maintain high quality recruitment practices means that researchers should expect some who are approached to decline the invitation to participate in their research.  Indeed, it should be considered an indicator of quality recruitment practices that potential participants feel able to say ‘no’ to research participation.  Which would ring the most alarm bells, the 100% conversion rate or the 75% conversion rate?

Each of the above challenges, and many more, can contribute to the concept of the Lasagna’s Law (first described by Louis Lasagna in 1970) or the idea that the number of patients who might participate in a research study falls dramatically as soon as the research commences.  In reality, the overestimation of potential recruitment is a well-known phenomena that results in recruitment often taking much longer than planned.  One action that might help to make recruitment strategies more effective would be to include clinical research nurses and other frontline research practitioners in pre-study planning and protocol development.  Most importantly, all researchers should focus greater effort on meeting the multiple challenges of recruiting to clinical research.

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