A time-varying covariate is added as a new field with daily time granularity and carried forward for missing entries. The name of the covariate can be specified by 'covariate'. By default, it is set to the 'testcd' (without any prefix).
Usage
add_covariate(
nif,
sdtm,
domain,
testcd,
covariate = NULL,
DTC_field = NULL,
DV_field = NULL,
TESTCD_field = NULL,
observation_filter = "TRUE",
duplicate_function = mean,
silent = NULL
)Arguments
- nif
A nif object.
- sdtm
The corresponding sdtm object.
- domain
The domain as character.
- testcd
The xxTESTCD with xx the domain name, as character.
- covariate
The name of the covariate, defaults to the testcd if NULL.
- DTC_field
The field to use as the date-time code for the observation. Defaults to the two-character domain name followed by 'DTC', if NULL.
- DV_field
The name of the DV field as character.
- TESTCD_field
The name of the TESTCD field. defaults to xxTESTCD (with xx the domain code), as character.
- observation_filter
A filter term for the
domain, as character.- duplicate_function
The function to apply if multiple covariate values are found by day.
- silent
Suppress messages, defaults to nif_option setting if NULL.
Value
A nif object with a new column added that contains the time-varying covariate values.
The name of this column is determined by the covariate parameter (or defaults to
the value of testcd if not specified). The covariate values are matched to the nif
object by USUBJID and date. For each subject, missing covariate values are filled
using the last observed value (carrying forward).
Examples
add_covariate(examplinib_poc_nif, examplinib_poc, "vs", "WEIGHT",
covariate = "wt")
#> ----- NONMEM input file (NIF) object -----
#> 1344 observations from 80 subjects across 1 study
#> Analytes: RS2023 and RS2023487A
#> 47 males (58.8%), 33 females (41.2%)
#>
#> Columns:
#> REF, ID, STUDYID, USUBJID, AGE, SEX, RACE, HEIGHT, WEIGHT, BMI, DTC, TIME,
#> NTIME, TAFD, TAD, PCELTM, EVID, AMT, ANALYTE, CMT, PARENT, TRTDY, METABOLITE,
#> DOSE, MDV, ACTARMCD, IMPUTATION, DV, BL_CREAT, BL_CRCL, wt
#>
#> Data (selected columns):
#> ID NTIME TIME TAD ANALYTE EVID CMT AMT DOSE DV
#> 1 0 0 0 RS2023 1 1 500 500 NA
#> 1 0 0 0 RS2023 0 2 0 500 0
#> 1 0 0 0 RS2023487A 0 3 0 500 0
#> 1 0.5 1 1 RS2023 0 2 0 500 636.683
#> 1 0.5 1 1 RS2023487A 0 3 0 500 135.126
#> 1 1 1.467 1.467 RS2023 0 2 0 500 1844.823
#> 1 1 1.467 1.467 RS2023487A 0 3 0 500 677.321
#> 1 1.5 2 2 RS2023 0 2 0 500 2773.308
#> 1 1.5 2 2 RS2023487A 0 3 0 500 1547.253
#> 1 2 2.467 2.467 RS2023 0 2 0 500 2539.54
#> 7612 more rows