Patient recruitment is a crucial step of clinical trials. Yet, it is also one that frequently poses many challenges and is one of the main factors contributing to untimely completion of clinical studies. In our experience as a Contract Research Organization (CRO), we have noticed that there are some common barriers to optimal patient engagement, and we have developed strategies to overcome them.
This article starts with an introduction to patient recruitment in clinical trials before we present five challenges that clinical researchers may face. We also share our recommendations to avoid such issues. Be sure to save this article for future reference and feel free to share it with someone who might be interested in the subject.
What is Patient Recruitment in Clinical Trials ?
Patient recruitment is one of the first steps of a clinical trial. It is the act of contacting, selecting and enrolling participants who will provide data to be analyzed in the study. It is the process of patient recruitment that will form the participant’s group which was defined in the study design.
Recruiting participants involves reaching out to potentially interested patients, informing them about the scope of the study, its objective and potential outcomes, and finally acquiring their formal consent to participate. It is, therefore, a complex process that, if poorly planned and executed, may result in insufficient enrollment rates and impact the trial outcomes.

Why Patient Recruitment is Important
Not only low recruitment rates, but also slow recruiting strategies can negatively impact the study. Extending the length of the trial to be able to reach the desired number of participants also means increasing the use of resources, spending more than what the initial budget allowed for and even losing credibility. Ultimately, patient recruitment is important because data quality depends on adequate sample size: some analysis might not even be made if there are not enough participants providing data, and the study might have to be abandoned.
Moreover, low recruitment rates or slow recruitment process affects not only the medical company or the CRO supporting it, but also patients, investors, and healthcare providers who count on the availability of the new medical product being developed. Having a strong, well-designed recruitment strategy is essential to start the clinical trial with a success-oriented approach.
Challenges in Patient Recruitment and How to Overcome Them
Knowing it is such an important step, you may wonder why it is still known as something so difficult to do. The success of patient recruitment in clinical trials depends on researcher related as well as patient related factors. You will see, in these five challenges that we listed, that problems in the study plan or in the recruitment strategy may cause low enrollment and high drop-out rates.
Challenge #1: Enrollment rates are low because of lack of awareness
People will not join a study they do not know to exist. While this might seem obvious, it still is the cause of the low enrollment rates of poorly promoted clinical trials. Some companies rely on the credibility of their name and neglect advertising, promoting and awareness raising.
Moreover, many people who would be ideal participants do not even know what a clinical trial is and how it is important to healthcare. Even if they are invited to join a study, they might ignore it as they would do with any common, uninteresting advertising campaign because they do not know how clinical research benefits patients like themselves.
How can I overcome this challenge ?
The starting point should be raising awareness about the role of clinical trials and the importance of patient’s participation. Medical companies, CROs and clinical researchers should unite in spreading the word about the patient’s role in clinical studies. This positive message should accompany every patient recruitment advertising campaign.
It is important to consider the unique patient group you are aiming to recruit for each clinical trial, as this will define what kind of advertising strategy you need to develop. If, for example, you need to recruit young participants who are 18 to 30 years old, you might focus on social media to spread the word about your clinical trial. While if you aim to recruit senior patients, traditional media such as newspapers and radio might be a better way to reach them.

Challenge #2: Patients refuse to participate because of fear of adverse events
When lack of awareness is not a problem, the wrong kind of awareness may be. Many people who know what a clinical trial is and even how patient’s participation is important may still refuse to enroll because they do not think it is safe enough or they do not trust the company conducting the study.
Knowing that they might face adverse events and have adverse reactions may stop people from enrolling, especially if communication is not clear enough and they are not informed of the possible positive outcomes in the same way. Some people might also be afraid to enroll because they think that adverse events are a consequence of clinical trials that they are forced to accept and will not receive help if necessary.
How can I overcome this challenge?
Good communication is clearly the solution to this problem. The way you first approach patients to inform them about the trial may change everything. The clinical trial should be presented as something that involves a lot of research and the work of experienced medical professionals. Shape your communication in a way that people can understand that they will be taking part in controlled, carefully planned clinical research, and not just in a common laboratory test.
Transparency is key to patient recruitment in clinical trials and participants should know about all possible adverse events. But they should also know about all the possible positive outcomes and how they will be receiving medical help if needed. The materials you use to promote the study should be written in clear, concise language and assure patients that the research team is ready to answer any questions and alleviate their concerns.
Challenge #3: Drop-out rates are high because participation is a burden on patients
Even when enrollment rates were acceptable, patient recruitment may still be challenging because of high drop-out rates. Usually, this happens because patients realize that participating in the study will take more time and effort than they thought and choose to leave the trial.
Complex and lengthy consent process, excessively long questionnaires, and too many trips to the study site are examples of increased burden on patients. Financial burden might also be a problem, if taking part in the study takes too much of the time of someone who works freelance, for example, or must commute to the study site and spend a lot in transportation.
How can I overcome this challenge?
Luckly, this challenge is on its way to being completely overcome by implementing decentralized clinical trials (DCTs). With eConsent, for example, it is easier to build customized, clear and concise consent digital forms that can be shared with patients, who will review and sign them comfortably at home, using their own devices. In fact, digitalizing all kinds of questionnaires and communication with patients, such as Patient Reported Outcomes (PROs), is a good way of reducing the burden on them and improving retention.
Telemedicine is also a great solution to reduce the number of visits to the study site and increase convenience for patients with busy agendas or reduced mobility. You may also include reimbursements and financial compensation in the study budget to reduce the financial burden on patients.
Challenge #4: Recruitment goals are not met because of too restrictive inclusion criteria
Problems in the study plan may cause challenges in patient recruitment in clinical trials. Inclusion and exclusion criteria are important to ensure that the patient group adequately reflects the population which will benefit from the new medical device or drug. However, sometimes excessively focused target groups may result in too restrictive inclusion criteria, making it difficult to find suitable participants and meet recruitment goals.
Focusing on a very limited age group, or on a too specific medical condition, may leave out participants who would be interested in participating and whose data might be actually useful to the study. Ambiguities in defining the target population in the study plan might also result in ineffective inclusion criteria, impacting patient recruitment.
How can I overcome this challenge ?
This is a challenge that experienced researchers and CROs do not worry about. With careful planning and some revising, the study plan will include a clear description of the target population and help defining feasible inclusion criteria.
Challenge #5: Patients are not interested in the study because of chances of receiving a placebo
This challenge is related to the lack of information and awareness, though it is a little more specific. Indeed, in some clinical trials, part of the patients will receive a placebo (an ineffective substance) instead of the treatment, so that the real effectiveness of the drug can be demonstrated by comparison.
If people believe that the chances that they will not receive any treatment are too high, they will not feel compelled to enroll. After all, most people will be expecting to benefit from some kind of treatment for their condition, even if it is still something being tested. In the end, it is lack of trust that may undermine patient recruitment in clinical trials.
How can I overcome this challenge?
You could start by gaining the patient’s trust and explaining to them that not all clinical trials use placebos. Many of them, in fact, compare new drugs with already existing medications, so people will still be receiving some kind of treatment.
In addition, ensure participants are well informed about the long-term impacts of a clinical trial. Even if they do not get any immediate benefit from their participation, they will be contributing to the development of an innovative treatment for their disease that can be available in the market sooner, if your clinical trial is successful due to their collaboration.
Summary
- Patient recruitment in clinical trials is the act of contacting, selecting and enrolling participants who will provide data to be analyzed in the study.
- Patient recruitment is important because data quality depends on adequate sample size.
- Some challenges to patient recruitment are low enrollment rates because of lack of awareness; patients’ fear of adverse events; high drop-out rates because of burdensome trials; and low recruitment rates because of too restrictive inclusion criteria and participant’s belief that they will receive a placebo.