Subject Visits and COVID-19

When the Guidance for Ongoing Studies Disrupted by COVID-19 was being developed, one of the issues was how to represent subject visits, given that regulators wanted to know about visits that were missed or modified due to the pandemic. The special purpose Subject Visits structure in the SDTMIG is quite rigid, including only certain variables, and with no provision for adding supplemental qualifiers. The Guidance included as a possible solution an events domain, called Visit Events (VE), which used a combination of existing events domain variables and supplemental qualifiers to represent the needed information.

In July 2022, the FDA published, in Appendix D, to their Technical Conformance Guide (TCG), a description of additional variables they want in a Subject Visits dataset. A dataset constructed to meet these requirements would depart from the standard, so validation software would create warnings and/or errors for the dataset. Such validation findings can be explained in PHUSE’s Clinical Study Data Reviewer’s Guide (cSDRG) Package.

The Subject Visits domain was originally proposed for the benefit of reviewers, and as originally proposed, it included only visits that took place. At that time, the dataset was a completely new idea, but reviewers and industry have now had experience with the dataset and have realized that including information about missed visits and about contacts that might not be conventionally thought of as visits, such as phone calls, would be useful. Spurred by the reviewer requirements described in the TCG, the public review version of SDTMIG v3.4 included SV as an events domain. As the result of public review feedback, the final SDTMIG v3.4 included this revised SV domain as a special purpose domain.

VE or SV?

The Guidance used the domain abbreviation VE for a custom domain to represent subject visits. However, feedback from FDA led to keeping the domain code SV, and feedback from public review led to keeping the classification of SV as a special purpose domain.

What do I submit now, under the current standard?

The FDA has stated their requirements in the TCG. An implementer submitting SV to the FDA would expect to follow their requirements and to explain validation findings in the cSDRG. PMDA has indicated they would accept SV datasets prepared to meet FDA requirements. Specific questions about a particular submission can, as always, be discussed with the regulatory authority.