This article provides a good example for documenting study subject site transfers, using existing SDTMIG domains and minimal supplemental qualifiers. Originally modeled for COVID studies, this approach could be used any time a study subject change sites during their participation in the study.
In the CDISC Guidance for Ongoing Studies Disrupted by COVID-19 v1.0 examples that document when the study subjects transferred from the site of original enrollment, to another site (e.g., when they could not continue at the site at which they originally enrolled) were included to demonstrate how to map data to SDTM v1.7. One of these examples used the existing SDTM Disposition (DS) domain, adding a record with the DSCAT value of “OTHER EVENT” to document any subject who transferred sites.
This example has been updated in SDTMIG v3.4, where DSEPCHGI as a standard variable:
Example 1
In Example 1, some subjects were transferred from the site where they were initially enrolled. Some of these transfers occurred when a site was no longer able to participate in the study because of the COVID-19 pandemic; one subject was transferred to a different site for a reason not related to COVID-19. Th transfers were represented in the DS domain in the category (DSCAT) "OTHER EVENT".
Row 1: Shows a subject who transferred to a different site for a reason unrelated to COVID-19.
Rows 2-7: Show subjects who were transferred to a different site because their original site was no longer able to participate in the study due to COVID-19.
DSEPCHGI = “Y” indicates that these changes were due to a pandemic. Note that DSEPCHGI is a new standard variable in SDTMIG v3.4. For prior versions, this variable would be non-standard and would be represented in a supplemental qualifier dataset.
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| Row | STUDYID | DOMAIN | USUBJID | DSSEQ | DSTERM | DSDECOD | DSCAT | DSEPCHGI | DSPARTY | DSPARTYID | DSSTDTC |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | ABC-234 | DS | 1001 | 3 | Subject moved and was transferred to a site in Florida | TRANSFERRED | OTHER EVENT | SITE | 21 | 2/3/20 | |
| 2 | ABC-234 | DS | 1301 | 4 | Subject transferred when original site was closed due to COVID-19 | TRANSFERRED | OTHER EVENT | Y | SITE | 16 | 4/6/20 |
| 3 | ABC-234 | DS | 1304 | 4 | Subject transferred when original site was closed due to COVID-19 | TRANSFERRED | OTHER EVENT | Y | SITE | 16 | 4/6/20 |
| 4 | ABC-234 | DS | 1308 | 3 | Subject transferred when original site was closed due to COVID-19 | TRANSFERRED | OTHER EVENT | Y | SITE | 16 | 4/6/20 |
| 5 | ABC-234 | DS | 1309 | 5 | Subject transferred when original site was closed due to COVID-19 | TRANSFERRED | OTHER EVENT | Y | SITE | 16 | 4/6/20 |
| 6 | ABC-234 | DS | 1310 | 3 | Subject transferred when original site was closed due to COVID-19 | TRANSFERRED | OTHER EVENT | Y | SITE | 16 | 4/6/20 |
| 7 | ABC-234 | DS | 1312 | 4 | Subject transferred when original site was closed due to COVID-19 | TRANSFERRED | OTHER EVENT | Y | SITE | 16 | 4/6/20 |
The event variables --PARTY and --PRTYID, originally developed for the Device Tracking and Disposition (DT) domain in the SDTMIG for Medical Devices v1.1, were used to represent the move from one site to another. The type of move (in this case "TRANSFERRED") was represented in --TERM; the party (in this case, "SITE") was represented in --PARTY, and the identifier for the party (in this case, site ID) was represented in --PRTYID. In the example dataset, only records for site transfers are represented. DSSEQ values were chosen to suggest that there were other disposition records for each subject. The event variables --PARTY and --PRTYID have been present in the SDTM since v1.4 and are not restricted to use in device studies or particular domains. The two variables are used in the SDTMIG for Medical Devices’ Device Tracking and Disposition (DT) domain to represent the move of a device from one party to another, with the person or organization accountable for the device at the conclusion of the action in DTPARTY. In the example above, the subject, rather than a device is being tracked, with the kind of organization in DSPARTY = "SITE" and the identifier for the site in DSPARTYID. This is the responsible site at the end of the transfer.
The example in the guide includes a part of the Demographics (DM) dataset to illustrate how sites transfers might be represented by adding a supplemental qualifier, SITEID1, for an additional site. An alternative would be to populate SITEID with "MULTIPLE" for subjects who transferred sites and to represent all sites, including the original site, in supplemental qualifiers. Either of these approaches could be used to account for multiple site transfers, by adding additional SITEIDn supplemental qualifiers. If you have questions about which approach regulators would prefer for particular a submission, you can, as always, discuss with the regulatory authority.
Note that representing multiple sites using supplemental qualifiers in DM does not indicate when the site transfer took place. The representation of site transfers in DS does provide the date of transfer in DSSTDTC.