21 March 2014

Challenge of Low Recruitment in Clinical Trial

What is subject recruitment and why is it important?

Participants in a clinical-trial are generally referred to as study subjects or volunteers. Depending on the study design, both healthy volunteers and patients suffering from a target disease (against which a study drug has been designed) would be eligible to participate in a clinical-trial. As clinicaltrials usually involve biomedical research to be conducted on human beings, lots of risk factors are involved in it. Thus, in order to protect the rights of the trial-participants and to ensure ethical conduct of the trial, a worldwide rule has been established that the decision to participate in any clinical-trial has to be made voluntarily; that is, the decision to participate or not in a clinicaltrial has to be made by free choice without any compulsion or obligation by the participant. Before participating in a-trial, the subjects must be informed thoroughly about the different aspects of the trial, details of the procedures involved, duration of the trial, the benefits as well the risks involved in participating in the-trial, insurance coverage etc., which can allow a participant to have clear knowledge of the trial-procedures and their obligations if they decide to participate in the-trial. Thus, after knowing all the benefits and anticipated risks of the clinical trial, the participant is considered to be knowledgeable enough to take a decision on voluntary basis regarding his/her participation in the clinical-trial.

One of the major challenges faced by clinical-trial teams worldwide is low subject recruitment for a study. Subject recruitment is often done at site (hospital or facility where the clinical-trial is conducted). It is a general practice that the clinical-trial team at the site have to approach a lot of potential participants who visit the site, counsel them, inform them about the benefits as well as risks involved in participating in the study, the insurance coverage they would be eligible for etc., prior to obtaining their consent for participation in the-trial. However, very often only a few people take the decision to participate in a-trial, due to the general myth that clinical-trials are often exploiting human subjects. Thus low subject recruitment is a major challenge in significant number of trials worldwide.

What are the consequences of low subject recruitment?

Low subject recruitment in clinical-trials can cause severe consequences and often hinder the successful completion of the-trial. Insufficient or delayed subject recruitment leads to prolongation of the-trial which in turn causes resources and budget constraints. This is in turn delays the process of obtaining a new approved treatment regime for a particular disease condition. There has also been several reports regarding termination of certain clinicaltrials due to poor subject recruitment. Thus for the successful completion of any clinicaltrial, subject recruitment becomes the most critical criteria.

Why do people hesitate to participate in a clinical trial?

One of the basic causes for not willing to participate in a clinical-trial is the subjects fear for the unknown outcome of the_trial. Since clinical-trials involve new drugs/devices/treatment regimen that have to be tested on human and could have unknown outcome /side effects, therefore people hesitate to participate in it, and often want to play safe and opt for an established market available therapy. In cases of some observational studies, the subjects may not get a direct benefit from participating in the_trial, for example, a genetic study to understand how a genetic-trait passes from one generation to other generation. This information is crucial for the enhancement of our understanding of the disease conditions that in turn help to develop a suitable drug/treatment, but since the subjects don't have a direct benefit, they do not agree to participate in such clinical-trials. Another popular reason for subject's denial to trial participation is the design of the study itself, example, grouping of patients in the_trials. Most of the drug_trials are either single or double blinded studies, that is, either the participating subject or both the subject and the physician do not know if the drug being tested will be administered to them. Also the process of randomization in clinical study allocates subjects to either treatment group or to the placebo group randomly and thus the subject is not aware of his treatment strategy. Such study designs often hinder the subject's participation in a clinical-trial.

Other minor reasons for low subject recruitment

The Investigators' enthusiasm for an ambitious subject recruitment in a trial which is often seen during the initial stages of most the trials disappear with time and does not prolong till the completion stages of the trial. The subject recruitment rate in a clinical-trial is influenced by the patients as well as the investigator's interests and efforts. Thus if either of the party loses interest, it effects the final outcome as visible in the recruitment numbers. Another possible reason for low recruitment could be subject withdrawal from the trial during the course of the trial. Such cases happen when subjects who have participated in the trial initially and have suffered some adverse events due to the usage of the new drug/treatment, and thus they would discontinue their participation. This decision to withdraw from the trial due to adverse events can also be made by the trial investigator at site for safety purposes of his/her patients. Few other reasons like long distance travel, time constraints etc., for follow up visits, can make the participant to lose interest and thus discontinue their participation from the trial.

Strategies to tackle low subject recruitment

Subject recruitment for a clinical-trial is a mammoth task, and the investigators at site along with their team follow a few strategies to handle this task. Counselling forms the most crucial step in this, and proper counseling of the patients about the benefits of the new drug/treatment regimen/medical device, educating them that participating in the clinicaltrial would help in the advancement of knowledge about their disease condition etc., and the direct benefits that they may get if they suffer from a disease condition for which there is no established treatment etc., might help in taking a positive decision towards subject participation in the clinical-trial. It must also be noted that subjects should not be lured into participation with direct monetary benefits; this is against law as it is considered unethical.


In this article, we have taken efforts to discuss one of the major problems in clinical trials worldwide, that is, subject recruitment; the consequences and causes for low recruitment and some of the strategies that a trial team at site would apply to tackle this most common problem.

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