The SDTM has been designed for backward compatibility; datasets prepared with prior versions should be compatible with v2.0. In most cases, this means that later versions may add new variables or correct textual errors, but do not eliminate variables or structures incorporated in prior versions. There are, however, isolated instances where some older variables may be deprecated in favor of newer, more functional variables.
Reorganization of Content
The content has been reorganized; the content of some sections has been relocated, some section names have changed, and some sections have been added, most notably:
- Content from Model Fundamentals has been moved to Section 2, Model Concepts and Terms – Organization of the SDTM, and Section 3, Study Subject Data.
- Content from Applying Model Fundamentals to Associated Persons is now in Section 4, Associated Persons Data and Section 6.6, Associated Persons Relationships.
- The table contained in Variables Used in Associated Persons Data is now in Section 4, Associated Persons Data.
- Content from Domain-specific Variables for General Observation Classes was moved to Section 3.1.1, The Interventions Observation Class, Section 3.1.2, The Events Observation Class, and Section 3.1.3, The Findings Observation Class.
- Content from SDTM Version History is now in Section 7, Changes from SDTM v1.8 to SDTM v2.0.
- The headings Representing Relationships among Datasets; Records and Datasets for Study References; and Variable, Dataset, and Section Changes and Additions were determined to be unnecessary extra section levels and were deleted.
In this version of the SDTM, tables are not numbered. No section contained more than 1 table, so table numbers added no information to section numbers.
Changes to Structures of Tables
All tables have been updated to include the following columns:
- Variable Name
- Variable Label
- Type
- Format
- Role
- Variable Qualified (when Role is "Variable Qualifier" or "Synonym Qualifier")
- Usage Restrictions
- Variable C-code
- Definition
- Notes
- Examples
Information previously in the Description column has been moved into or replaced by text in new columns.
- Text indicating that variables are not to be used for human clinical trials now appears in the Usage Restrictions column.
- Examples formerly in the Description column were moved into the Examples column. Example values are enclosed in quotation marks.
- Other content in the Description column is now in the Notes column, except that for variables with definitions, definition-like text has been removed.
- Not all variables currently have approved definitions. Missing variable definitions will be added in future versions of the SDTM as they are developed and approved.
- Not all variables currently have approved c-codes. Missing c-codes will be added in future versions of the SDTM as they are developed and approved.
Variables that were previously represented in a separate table of Domain-Specific Variables for General Observation Classes have been moved to tables of variables for the appropriate general observation class, with a note in the Usage Restrictions column giving the domain(s) to which use is restricted. The role of the domain-specific variable --BEATNO was changed to Identifier, so it was included in Section 3.1.4, Identifiers for All Classes, rather than Section 3.1.3, The Findings Observation Class.
Usage Restrictions previously mentioned only in the SDTMIG and/or the Standard for Exchange of Nonclinical Data Implementation Guide (SENDIG) were added:
- --OCCUR may not be used in the AE domain.
- --STDTC, --STDY, --XSTDY, and --CHSTDY may not be used in Findings domains.
For each general observation class, 1 table of variables was created by combining former tables for the topic variable and the qualifier variables.
Changes to Datasets and Variables
The Subject Visits domain, which was a special-purpose domain, has been moved to an Events class domain. The variable "SVUPDES" became a domain-specific Events class variable.
A new relationships domain, Related Specimens (RELSPEC), has been added. This domain, first introduced in the provisional SDTMIG-PGx (now deprecated), had not previously been a part of the SDTM. RELSPEC was added to this version of the SDTM because the domain was added to SDTMIG v3.4.
SDTM v2.0 does not identify any proposed deprecated variables, as there are no variables to be deprecated at this time.
The variable APID was removed from Section 3.1.4, Identifiers for All Classes, because APID is only allowed in AP domains. It is still listed in Section 3, Associated Persons Data.
New variables have been added to the following sections:
- Section 3.1.1, The Interventions Observation Class
- Section 3.1.2, The Events Observation Class
- Section 3.1.3, The Findings Observation Class
- Section 3.1.5, Timing Variables for All Classes
- Section 3.2.3.1, Subject Elements
The role of the --LOINC variable in Section 3.1.3, The Findings Observation Class, was changed from Synonym Qualifier of --TESTCD to Record Qualifier, because a single value of --TESTCD may be associated with multiple values of --LOINC, depending on the values of other variables, such as --SPEC and --METHOD.
The order of --METHOD within Interventions Variables in Section 3.1.1, The Interventions Observation Class, was changed so that the variable appears after --PORTOT, rather than after --LOC. This change was made so that --METHOD would appear after the variable qualifiers of --LOC rather than immediately after --LOC.
A number of changes are proposed for the next version of the SDTM. See Section 8, Proposed Future Changes to the SDTM, for the rationale for these proposed changes.
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