Same Subject Assigned Two USUBJIDs (Screening/Rescreening) in Locked Study

[amiteshm]

In our study (already locked), we found an issue where the same subject has been assigned two different USUBJIDs — one at screening and another at rescreening.

This creates challenges because:

• Normally, each subject should have only one unique USUBJID across the study.

• Simply replacing the earlier USUBJID with the rescreened one could cause problems, since some datasets may have flags or derivations tied to SUBJID/USUBJID.

• Domains like DS, SE, and SV are especially affected.

At the output level, the impact is minimal — it only affects disposition screen counts and screen failure counts.

Our question: Is it acceptable to leave ADaM and SDTM datasets as-is (with the duplicate USUBJID issue) and instead address this only in the disposition output? We could then provide an explanation of this approach in the Reviewer’s Guide for transparency.

Has anyone encountered a similar issue before? If so, how did you resolve it?

Any advice or examples would be greatly appreciated.

[himself]

Hi Amiteshm,

I think the impact of duplicate USUBJIDs mostly shows in disposition domain counts and screen failure summaries with minimal effect at other output levels, the SDTM and ADaM datasets should ideally conform to the uniqueness of USUBJID for consistency and regulatory acceptance. If this is not possible due to study specifics, full transparency with justification in the Reviewer's Guide and consistent flagging of these cases in DS and SE is essential.

Upon checking this under FDA’s TCG states that the primary enrollment (or the single DM record) goes into DM, and additional screenings/enrollments should be represented in a custom domain with a DM‑like structure (often called DC – Demographics as Collected), not as extra DM rows nor with second USUBJIDs.

For more of this can have a check at the following:Exploration on Demographic as Collected (DC) Domain to Handle Multiple Screenings in SDTM