requirePriorObservation: Restrict cohort on prior observation

In CohortConstructor: Build and Manipulate Study Cohorts Using a Common Data Model

Restrict cohort on prior observation

Description

requirePriorObservation() filters cohort records, keeping only records where individuals satisfy the specified prior observation criteria.

Usage

requirePriorObservation(
  cohort,
  minPriorObservation,
  cohortId = NULL,
  indexDate = "cohort_start_date",
  atFirst = FALSE,
  name = tableName(cohort)
)

Arguments

cohort	A cohort table in a cdm reference.
minPriorObservation	A minimum number of continuous prior observation days in the database.
cohortId	Vector identifying which cohorts to modify (cohort_definition_id or cohort_name). If NULL, all cohorts will be used; otherwise, only the specified cohorts will be modified, and the rest will remain unchanged.
indexDate	Variable in cohort that contains the date to compute the demographics characteristics on which to restrict on.
atFirst	If FALSE the requirement will be applied to all records, if TRUE, it will only be required for the first entry of each subject.
name	Name of the new cohort table created in the cdm object.

Value

The cohort table with only records for individuals satisfying the prior observation requirement

Examples

library(CohortConstructor)
if(isTRUE(omock::isMockDatasetDownloaded("GiBleed"))){
cdm <- mockCohortConstructor()
cdm$cohort1 |>
  requirePriorObservation(indexDate = "cohort_start_date",
                          minPriorObservation = 365)
}

CohortConstructor documentation built on Nov. 5, 2025, 6:53 p.m.