documentation:cdm:cohort

COHORT table

THIS IS OUTDATED. All documentation is now on the github wiki. Please refer there or to the CDM working group for more information

The COHORT table contains records of subjects that satisfy a given set of criteria for a duration of time. The definition of the cohort is contained within the COHORT_DEFINITION table. Cohorts can be constructed of patients (Persons), Providers or Visits.

Field	Required	Type	Description
cohort_definition_id	Yes	integer	A foreign key to a record in the COHORT_DEFINITION table containing relevant Cohort Definition information.
subject_id	Yes	integer	A foreign key to the subject in the cohort. These could be referring to records in the PERSON, PROVIDER, VISIT_OCCURRENCE table.
cohort_start_date	Yes	date	The date when the Cohort Definition criteria for the Person, Provider or Visit first match.
cohort_end_date	Yes	date	The date when the Cohort Definition criteria for the Person, Provider or Visit no longer match or the Cohort membership was terminated.

Conventions

The core of a Cohort is the unifying definition or feature of the Cohort. This is captured in the cohort_definition_id. For example, Cohorts can include patients diagnosed with a specific condition, patients exposed to a particular drug, or Providers who have performed a specific Procedure.
Cohort records must have a Start Date
Cohort records must have an End Date, but may be set to Start Date or could have applied a censored date using the Observation Period Start Date.
Cohort records must contain a Subject Id, which can refer to the Person, Provider, or Visit record. The Cohort Definition will define the type of subject through the subject concept id.