derive_var_base: Derive Baseline Variables

In admiral: ADaM in R Asset Library

Derive Baseline Variables

Description

Derive baseline variables, e.g. BASE or BNRIND, in a BDS dataset.

Note: This is a wrapper function for the more generic derive_vars_merged().

Usage

derive_var_base(
  dataset,
  by_vars,
  source_var = AVAL,
  new_var = BASE,
  filter = ABLFL == "Y"
)

Arguments

dataset	Input dataset The variables specified by the by_vars and source_var arguments are expected to be in the dataset. Default value none
by_vars	Grouping variables Grouping variables uniquely identifying a set of records for which to calculate new_var. Default value none
source_var	The column from which to extract the baseline value, e.g. AVAL Default value AVAL
new_var	The name of the newly created baseline column, e.g. BASE Default value BASE
filter	The condition used to filter dataset for baseline records. By default ABLFL == "Y" Default value ABLFL == "Y"

Details

For each by_vars group, the baseline record is identified by the condition specified in filter which defaults to ABLFL == "Y". Subsequently, every value of the new_var variable for the by_vars group is set to the value of the source_var variable of the baseline record. In case there are multiple baseline records within by_vars an error is issued.

Value

A new data.frame containing all records and variables of the input dataset plus the new_var variable

See Also

BDS-Findings Functions that returns variable appended to dataset: derive_basetype_records(), derive_var_analysis_ratio(), derive_var_anrind(), derive_var_atoxgr(), derive_var_atoxgr_dir(), derive_var_chg(), derive_var_ontrtfl(), derive_var_pchg(), derive_var_shift(), derive_vars_crit_flag()

Examples

library(tibble)

dataset <- tribble(
  ~STUDYID, ~USUBJID, ~PARAMCD, ~AVAL, ~AVALC,   ~AVISIT,    ~ABLFL, ~ANRIND,
  "TEST01", "PAT01", "PARAM01", 10.12, NA,       "Baseline", "Y",    "NORMAL",
  "TEST01", "PAT01", "PARAM01", 9.700, NA,       "Day 7",    NA,     "LOW",
  "TEST01", "PAT01", "PARAM01", 15.01, NA,       "Day 14",   NA,     "HIGH",
  "TEST01", "PAT01", "PARAM02", 8.350, NA,       "Baseline", "Y",    "LOW",
  "TEST01", "PAT01", "PARAM02",    NA, NA,       "Day 7",    NA,     NA,
  "TEST01", "PAT01", "PARAM02", 8.350, NA,       "Day 14",   NA,     "LOW",
  "TEST01", "PAT01", "PARAM03",    NA, "LOW",    "Baseline", "Y",    NA,
  "TEST01", "PAT01", "PARAM03",    NA, "LOW",    "Day 7",    NA,     NA,
  "TEST01", "PAT01", "PARAM03",    NA, "MEDIUM", "Day 14",   NA,     NA,
  "TEST01", "PAT01", "PARAM04",    NA, "HIGH",   "Baseline", "Y",    NA,
  "TEST01", "PAT01", "PARAM04",    NA, "HIGH",   "Day 7",    NA,     NA,
  "TEST01", "PAT01", "PARAM04",    NA, "MEDIUM", "Day 14",   NA,     NA
)

## Derive `BASE` variable from `AVAL`
derive_var_base(
  dataset,
  by_vars = exprs(USUBJID, PARAMCD),
  source_var = AVAL,
  new_var = BASE
)

## Derive `BASEC` variable from `AVALC`
derive_var_base(
  dataset,
  by_vars = exprs(USUBJID, PARAMCD),
  source_var = AVALC,
  new_var = BASEC
)

## Derive `BNRIND` variable from `ANRIND`
derive_var_base(
  dataset,
  by_vars = exprs(USUBJID, PARAMCD),
  source_var = ANRIND,
  new_var = BNRIND
)

admiral documentation built on June 26, 2025, 1:08 a.m.