Restrict cohort to only the first cohort record per subject

Filter the cohort table keeping only the first cohort record per subject.

Usage

requireIsFirstDrugEntry(
  cohort,
  cohortId = NULL,
  name = omopgenerics::tableName(cohort)
)

Arguments

cohort

A cohort_table object.

cohortId

A cohort definition id to restrict by. If NULL, all cohorts will be included.

name

Name of the new cohort table, it must be a length 1 character vector.

Value

The cohort table having applied the first entry requirement.

Examples

# \donttest{
library(DrugUtilisation)
library(dplyr)

cdm <- mockDrugUtilisation()

cdm$cohort1 <- cdm$cohort1 |>
  requireIsFirstDrugEntry()

attrition(cdm$cohort1) |> glimpse()
#> Rows: 6
#> Columns: 7
#> $ cohort_definition_id <int> 1, 1, 2, 2, 3, 3
#> $ number_records       <int> 2, 2, 3, 3, 5, 5
#> $ number_subjects      <int> 2, 2, 3, 3, 5, 5
#> $ reason_id            <int> 1, 2, 1, 2, 1, 2
#> $ reason               <chr> "Initial qualifying events", "require is the firs…
#> $ excluded_records     <int> 0, 0, 0, 0, 0, 0
#> $ excluded_subjects    <int> 0, 0, 0, 0, 0, 0
# }