Defining and Reporting Subject Enrollment
Along with research milestones, subject enrollment must be reported when active research requires continuing review. Determining when a subject is ‘enrolled’ however, can be challenging as use of the term can vary depending on the nature of the research and who you’re communicating with (e.g., an Institutional Review Board [IRB] vs. a study sponsor).
When is a subject ‘enrolled’ in the research?
The Research Subjects Review Board (RSRB) considers a subject enrolled in the research once they have provided consent to participate.
For simple studies, determining enrollment should be relatively straightforward–all subjects who have provided written or verbal consent should be counted as ‘enrolled’ and the number reported as ‘enrolled’ should be consistent with your study documentation (e.g., the number of maintained signed consents, the number of subjects identified on an enrollment log, the number of completed surveys).
screening procedures
For studies that involve screening procedures (i.e., where a subject undergoes study-specific procedures to validate eligibility [e.g., oral medical history or blood draw]), reporting enrollment can be a bit more complicated.
As a general rule of thumb, subjects should be counted as ‘enrolled’ after written or verbal consent to perform the screening procedures is provided. For example:
- When a medical or academic record is reviewed to confirm eligibility prior to subject recruitment and/or consent, the subject should only be counted as ‘enrolled’ when eligibility is confirmed and they consent to participate. If a subject’s medical or academic record is reviewed and they are determined to be ineligible and therefore are never approached to participate in the research, they should not be counted as ‘enrolled’.
- When a subject is verbally asked questions to validate eligibility, prior to written or verbal consent, the subject should only be counted as ‘enrolled’ when eligibility is confirmed and they consent to participate. If a subject is verbally queried prior to written or verbal consent and they are determined to be ineligible and therefore consent is never obtained, they should not be counted as ‘enrolled’.
- When a subject provides written or verbal consent to undergo formal screening procedures (e.g., physical exam, neurocognitive assessment), the subject should be counted as ‘enrolled’ regardless of whether eligibility is confirmed via the screening procedures. In the event, a subject provides consent and is subsequently determined to be ineligible following screening procedures, they would then be considered a ‘screen failure’.
Subject enrollment FAQs
First and foremost, the study protocol should specifically indicate when an individual subject is permitted to participate in the research more than once. The circumstances for allowing this participation will depend on the nature of the research, as will how subjects should be counted in enrollment totals. Generally, subjects should only be counted once toward the enrollment total. In the event an individual subject’s participation in the research, is counted more than once in the enrollment total (e.g., a study that allows screen failures to re-screen for participation after a specific waiting period or if the individual participates in a study more than once and signs a new consent form each time they enroll), the protocol should clarify how enrollment totals are being determined, and how subjects will be counted if they enroll in the study multiple times.
For studies involving a secondary data analysis, chart reviews and/or specimen analysis approved with a waiver of consent, subjects should be counted as ‘enrolled’ when they have been identified as eligible for the study and the study team plans to collect or use their data/specimens.
As stated above, a subject is considered enrolled in the research once they have provided consent to participate. Activities that occur following consent–subject withdrawal, investigator-initiated subject withdrawal, lost to follow-up, or subject death (due to causes related or unrelated to study participation)–do not affect how enrollment totals are calculated. E.g., if 10 subjects are enrolled and 1 subject withdrawals, 10 subjects should still be reported as ‘enrolled’.
To report withdrawals (both subject withdrawals and investigator-initiated subject withdrawals) in Click IRB, leave the ‘NO subjects withdrew from the study’ checkbox in Question 4 of the Continuing Review form unchecked and insert a comment into Question 5 or attach additional supporting documentation in Question 6.