derive_var_relative_flag: Flag Observations Before or After a Condition is Fulfilled

In Roche-GSK/admiral: ADaM in R Asset Library

Flag Observations Before or After a Condition is Fulfilled

Description

Flag all observations before or after the observation where a specified condition is fulfilled for each by group. For example, the function could be called to flag for each subject all observations before the first disease progression or to flag all AEs after a specific AE.

Usage

derive_var_relative_flag(
  dataset,
  by_vars,
  order,
  new_var,
  condition,
  mode,
  selection,
  inclusive,
  flag_no_ref_groups = TRUE,
  check_type = "warning"
)

Arguments

dataset	Input dataset The variables specified by the by_vars and order arguments are expected to be in the dataset. Default value none
by_vars	Grouping variables Default value none
order	Sort order Within each by group the observations are ordered by the specified order. For handling of NAs in sorting variables see Sort Order. Permitted values list of expressions created by exprs(), e.g., exprs(ADT, desc(AVAL)) Default value none
new_var	New variable The variable is added to the input dataset and set to "Y" for all observations before or after the condition is fulfilled. For all other observations it is set to NA. Default value none
condition	Condition for Reference Observation The specified condition determines the reference observation. In the output dataset all observations before or after (selection argument) the reference observation are flagged. Default value none
mode	Selection mode (first or last) If "first" is specified, for each by group the observations before or after (selection argument) the observation where the condition (condition argument) is fulfilled the first time is flagged in the output dataset. If "last" is specified, for each by group the observations before or after (selection argument) the observation where the condition (condition argument) is fulfilled the last time is flagged in the output dataset. Permitted values "first", "last" Default value none
selection	Flag observations before or after the reference observation? Permitted values "before", "after" Default value none
inclusive	Flag the reference observation? Permitted values TRUE, FALSE Default value none
flag_no_ref_groups	Should by groups without reference observation be flagged? Permitted values TRUE, FALSE Default value TRUE
check_type	Check uniqueness? If "warning" or "error" is specified, the specified message is issued if the observations of the input dataset are not unique with respect to the by variables and the order. Permitted values "none", "warning", "error" Default value "warning"

Details

For each by group (by_vars argument) the observations before or after (selection argument) the observations where the condition (condition argument) is fulfilled the first or last time (order argument and mode argument) is flagged in the output dataset.

Value

The input dataset with the new variable (new_var) added

See Also

General Derivation Functions for all ADaMs that returns variable appended to dataset: derive_var_extreme_flag(), derive_var_joined_exist_flag(), derive_var_merged_ef_msrc(), derive_var_merged_exist_flag(), derive_var_merged_summary(), derive_var_obs_number(), derive_vars_cat(), derive_vars_computed(), derive_vars_joined(), derive_vars_merged(), derive_vars_merged_lookup(), derive_vars_transposed()

Examples

library(tibble)
library(dplyr, warn.conflicts = FALSE)

# Flag all AEs after the first COVID AE
adae <- tribble(
  ~USUBJID, ~ASTDY, ~ACOVFL, ~AESEQ,
  "1",           2, NA,           1,
  "1",           5, "Y",          2,
  "1",           5, NA,           3,
  "1",          17, NA,           4,
  "1",          27, "Y",          5,
  "1",          32, NA,           6,
  "2",           8, NA,           1,
  "2",          11, NA,           2,
)

derive_var_relative_flag(
  adae,
  by_vars = exprs(USUBJID),
  order = exprs(ASTDY, AESEQ),
  new_var = PSTCOVFL,
  condition = ACOVFL == "Y",
  mode = "first",
  selection = "after",
  inclusive = FALSE,
  flag_no_ref_groups = FALSE
)

response <- tribble(
  ~USUBJID, ~AVISITN, ~AVALC,
  "1",      0,        "PR",
  "1",      1,        "CR",
  "1",      2,        "CR",
  "1",      3,        "SD",
  "1",      4,        "NE",
  "2",      0,        "SD",
  "2",      1,        "PD",
  "2",      2,        "PD",
  "3",      0,        "SD",
  "4",      0,        "SD",
  "4",      1,        "PR",
  "4",      2,        "PD",
  "4",      3,        "SD",
  "4",      4,        "PR"
)

# Flag observations up to first PD for each patient
response %>%
  derive_var_relative_flag(
    by_vars = exprs(USUBJID),
    order = exprs(AVISITN),
    new_var = ANL02FL,
    condition = AVALC == "PD",
    mode = "first",
    selection = "before",
    inclusive = TRUE
  )

# Flag observations up to first PD excluding baseline (AVISITN = 0) for each patient
response %>%
  restrict_derivation(
    derivation = derive_var_relative_flag,
    args = params(
      by_vars = exprs(USUBJID),
      order = exprs(AVISITN),
      new_var = ANL02FL,
      condition = AVALC == "PD",
      mode = "first",
      selection = "before",
      inclusive = TRUE
    ),
    filter = AVISITN > 0
  ) %>%
  arrange(USUBJID, AVISITN)

Roche-GSK/admiral documentation built on April 14, 2025, 12:36 p.m.