Recruitment

Explanation

The main goal of recruitment is to meet the target sample size (Item 19). However, recruitment difficulties are common in clinical trials.(310, 311) For example, a review of trials from 2004 to 2016 funded by the United Kingdom’s Health Technology Assessment Programme found that 44% did not reach their recruitment targets.(312) Inadequate enrolment will reduce statistical power and can lead to early trial stoppage or to extensions with delayed results and greater costs.

Strategies to promote adequate enrolment are thus important to consider during trial planning. Recruitment strategies can vary depending on the trial topic, context, and site. Different recruitment methods can substantially affect the number and type of trial participants recruited(207, 310, 313, 314) and can incur different costs.(315-317) Design issues such as the number and stringency of eligibility criteria will also directly affect the number of eligible trial participants.

While most trials will use strategies to promote enrolment of participants, this information is often incompletely reported in trial protocols.(9, 10, 318) For example, reviews of two samples of 108 and 292 trial protocols from 2016 found that less than 44% of protocols reported the location of recruitment, persons who will recruit, or expected recruitment rate.(9, 10)

Protocol descriptions of where participants will be recruited (e.g., primary care clinic, community), by whom (e.g., surgeon), when (e.g., time after diagnosis), and how (e.g., advertisements, review of health records) can be helpful for assessing the feasibility of achieving the target sample size and the applicability of the trial results in practice. Other relevant information to explicitly provide in the protocol includes expected recruitment rates, duration of the recruitment period, plans to monitor recruitment during the trial, and any financial or non-financial incentives provided to trial investigators (Item 3a) or participants for enrolment.

Summary of key elements to address

● Planned strategies to promote adequate enrolment (e.g., advertisements, pre-screening of health records, reducing participant burden)

● Where participants will be recruited (e.g., primary care clinic, community), by whom (e.g., surgeon), and when (e.g., time period after diagnosis)