Understanding SDTM Trial Summary Domain: ACTSUB vs Screen Failures
In the world of clinical data management, the Study Data Tabulation Model (SDTM) plays a vital role in organizing and submitting clinical trial data to regulatory agencies. One of the most essential domains in SDTM is the Trial Summary (TS) domain, which provides key information about the clinical trial itself.
In this blog post, we will explore the Actual Number of Subjects (ACTSUB) and how it differs from screen failures. We will also reference regulatory guidelines and SDTM Implementation Guides to ensure a deeper understanding.
What is the TS Domain?
The Trial Summary (TS) domain contains high-level information about the clinical trial. This includes essential data such as the number of subjects, the start and end dates of the trial, trial objectives, and much more. The TSPARMCD variable defines various parameters such as the number of subjects or study arms in the trial.
What is TSPARMCD=ACTSUB?
ACTSUB stands for the "Actual Number of Subjects" in a clinical trial. This variable represents the number of participants who actually started the treatment or intervention after passing the screening phase.
"The actual number of subjects refers to the total number of participants who were enrolled in the study and received at least one treatment or underwent a key study procedure."
This means that screen failures—subjects who were screened but did not qualify to proceed—are typically excluded from this count. Regulatory agencies such as the FDA and EMA expect only those subjects who participated in the study to be counted under ACTSUB.
How Are Screen Failures Captured in the TS Domain?
Screen failures are accounted for separately from ACTSUB in most cases. For instance, the TS domain may contain a different variable like TSPARMCD=SCRSUB, which captures the number of subjects who were screened. This would include those who did not pass the screening process.
Example Scenario: ACTSUB and Screen Failures
Let’s consider a hypothetical trial with 200 subjects:
- 250 subjects were screened.
- 50 of those subjects were screen failures (they did not meet eligibility criteria).
- The remaining 200 subjects were enrolled in the trial and participated in the treatment.
In this scenario, TSPARMCD=ACTSUB would be recorded as 200, while TSPARMCD=SCRSUB would be recorded as 250 to include all screened subjects, both successful and failures.
References and Guidelines
To further explore this topic, you can review the following references:
- CDISC SDTM Documentation - Official SDTM documentation by CDISC.
- FDA Clinical Trial Data Requirements - The U.S. Food and Drug Administration’s guidelines on submitting clinical trial data.
- EMA Clinical Trial Data Submission Guidelines - European Medicines Agency’s resources on clinical trial data.
- SDTM Implementation Guide (SDTM IG) - Implementation guidelines from CDISC for using SDTM in clinical trials.
