SDTM SU Assumptions

Substance use information may be independent of planned study evaluations, or may be a key outcome (e.g., planned evaluation) of a clinical trial.

1. In many clinical trials, detailed substance use information as provided for in the domain model above may not be required (e.g., the only information collected may be a response to the question “Have you ever smoked tobacco?”); in such cases, many of the qualifier variables would not be submitted.
2. SU may contain responses to questions about use of prespecified substances as well as records of substance use collected as free text.

1. SUTRT captures the verbatim or the prespecified text collected for the substance. It is the topic variable for the SU dataset. SUTRT is a required variable and must have a value.
2. SUMODIFY is a permissible variable and should be included if coding is performed and the sponsor’s procedure permits modification of a verbatim substance use term for coding. The modified term is listed in SUMODIFY. The variable may be populated as per the sponsor’s procedures.
3. SUDECOD is the preferred term derived by the sponsor from the coding dictionary if coding is performed. It is a permissible variable. Where deemed necessary by the sponsor, the verbatim term (SUTRT) should be coded using a standard dictionary such as WHO Drug. The sponsor is expected to provide the dictionary name and version used to map the terms utilizing the external codelist element in the Define-XML document.

1. SUCAT and SUSCAT should not be redundant with the domain code or dictionary classification provided by SUDECOD, or with SUTRT. That is, they should provide a different means of defining or classifying SU records. For example, a sponsor may be interested in identifying all substances that the investigator feels might represent opium use, and to collect such use on a separate CRF page. This categorization might differ from the categorization derived from the coding dictionary.
2. SUGRPID may be used to link (or associate) different records together to form a block of related records within SU at the subject level (see Section 4.2.6, SEND - Grouping Variables and Categorization). It should not be used in place of SUCAT or SUSCAT.

1. SUSTDTC and SUENDTC may be populated as required.
2. If substance use information is collected more than once within the CRF (indicating that the data are visit-based) then VISITNUM would be added to the domain as an additional timing variable. VISITDY and VISIT would then be permissible variables.