Skip to contents

Derive on-treatment flag (ONTRTFL) in an ADaM dataset with a single assessment date (e.g ADT) or event start and end dates (e.g. ASTDT/AENDT).

Usage

derive_var_ontrtfl(
  dataset,
  new_var = ONTRTFL,
  start_date,
  end_date = NULL,
  ref_start_date,
  ref_end_date = NULL,
  ref_end_window = 0,
  filter_pre_timepoint = NULL,
  span_period = NULL
)

Arguments

dataset

Input dataset.

Required columns are start_date, end_date, ref_start_date and ref_end_date.

new_var

On-treatment flag variable name to be created.

Default is ONTRTFL.

start_date

The start date (e.g. AESDT) or assessment date (e.g. ADT) Required; A date or date-time object column is expected.

Refer to derive_vars_dt() to impute and derive a date from a date character vector to a date object.

end_date

The end date of assessment/event (e.g. AENDT) A date or date-time object column is expected.

Refer to derive_vars_dt() to impute and derive a date from a date character vector to a date object.

Optional; Default is null. If the used and date value is missing on an observation, it is assumed the medication is ongoing and ONTRTFL is set to "Y".

ref_start_date

The lower bound of the on-treatment period Required; A date or date-time object column is expected.

Refer to derive_vars_dt() to impute and derive a date from a date character vector to a date object.

ref_end_date

The upper bound of the on-treatment period A date or date-time object column is expected.

Refer to derive_vars_dt() to impute and derive a date from a date character vector to a date object.

Optional; This can be null and everything after ref_start_date will be considered on-treatment. Default is NULL.

ref_end_window

A window to add to the upper bound ref_end_date measured in days (e.g. 7 if 7 days should be added to the upper bound) Optional; default is 0.

filter_pre_timepoint

An expression to filter observations as not on-treatment when date = ref_start_date. For example, if observations where VSTPT = PRE should not be considered on-treatment when date = ref_start_date, filter_pre_timepoint should be used to denote when the on-treatment flag should be set to null. Optional; default is NULL.

span_period

A "Y" scalar character. If "Y", events that started prior to the ref_start_dateand are ongoing or end after the ref_start_date are flagged as "Y". Optional; default is NULL.

Value

The input dataset with an additional column named ONTRTFL with a value of "Y" or NA

Details

On-Treatment is calculated by determining whether the assessment date or start/stop dates fall between 2 dates. The following logic is used to assign on-treatment = "Y":

  1. start_date is missing and ref_start_dateis non-missing

  2. No timepoint filter is provided (filter_pre_timepoint) and both start_date and ref_start_date are non-missing and start_date = ref_start_date

  3. A timepoint is provided (filter_pre_timepoint) and both start_date and ref_start_date are non-missing and start_date = ref_start_date and the filter provided in filter_pre_timepoint is not true.

  4. ref_end_date is not provided and ref_start_date < start_date

  5. ref_end_date is provided and ref_start_date < start_date <= ref_end_date + ref_end_window.

If the end_date is provided and the end_date < ref_start_date then the ONTRTFL is set to NULL.This would be applicable to cases where the start_date is missing and ONTRTFL has been assigned as "Y" above.

If the span_period is specified as "Y", this allows the user to assign ONTRTFL as "Y" to cases where the record started prior to the ref_start_date and was ongoing or ended after the ref_start_date.

Any date imputations needed should be done prior to calling this function.

See also

Author

Alice Ehmann, Teckla Akinyi

Examples

library(tibble)
library(dplyr)
library(lubridate, warn.conflict = FALSE)

advs <- tribble(
  ~USUBJID, ~ADT,              ~TRTSDT,           ~TRTEDT,
  "P01",    ymd("2020-02-24"), ymd("2020-01-01"), ymd("2020-03-01"),
  "P02",    ymd("2020-01-01"), ymd("2020-01-01"), ymd("2020-03-01"),
  "P03",    ymd("2019-12-31"), ymd("2020-01-01"), ymd("2020-03-01")
)
derive_var_ontrtfl(
  advs,
  start_date = ADT,
  ref_start_date = TRTSDT,
  ref_end_date = TRTEDT
)
#> # A tibble: 3 x 5
#>   USUBJID ADT        TRTSDT     TRTEDT     ONTRTFL
#>   <chr>   <date>     <date>     <date>     <chr>  
#> 1 P01     2020-02-24 2020-01-01 2020-03-01 Y      
#> 2 P02     2020-01-01 2020-01-01 2020-03-01 Y      
#> 3 P03     2019-12-31 2020-01-01 2020-03-01 NA     

advs <- tribble(
  ~USUBJID, ~ADT,              ~TRTSDT,           ~TRTEDT,
  "P01",    ymd("2020-07-01"), ymd("2020-01-01"), ymd("2020-03-01"),
  "P02",    ymd("2020-04-30"), ymd("2020-01-01"), ymd("2020-03-01"),
  "P03",    ymd("2020-03-15"), ymd("2020-01-01"), ymd("2020-03-01")
)
derive_var_ontrtfl(
  advs,
  start_date = ADT,
  ref_start_date = TRTSDT,
  ref_end_date = TRTEDT,
  ref_end_window = 60
)
#> # A tibble: 3 x 5
#>   USUBJID ADT        TRTSDT     TRTEDT     ONTRTFL
#>   <chr>   <date>     <date>     <date>     <chr>  
#> 1 P01     2020-07-01 2020-01-01 2020-03-01 NA     
#> 2 P02     2020-04-30 2020-01-01 2020-03-01 Y      
#> 3 P03     2020-03-15 2020-01-01 2020-03-01 Y      

advs <- tribble(
  ~USUBJID, ~ADTM,                      ~TRTSDTM,                   ~TRTEDTM,
  "P01",    ymd_hm("2020-01-02T12:00"), ymd_hm("2020-01-01T12:00"), ymd_hm("2020-03-01T12:00"),
  "P02",    ymd("2020-01-01"),          ymd_hm("2020-01-01T12:00"), ymd_hm("2020-03-01T12:00"),
  "P03",    ymd("2019-12-31"),          ymd_hm("2020-01-01T12:00"), ymd_hm("2020-03-01T12:00"),
) %>%
  mutate(TPT = c(NA, "PRE", NA))
derive_var_ontrtfl(
  advs,
  start_date = ADTM,
  ref_start_date = TRTSDTM,
  ref_end_date = TRTEDTM,
  filter_pre_timepoint = TPT == "PRE"
)
#> # A tibble: 3 x 6
#>   USUBJID ADTM                TRTSDTM             TRTEDTM             TPT  
#>   <chr>   <dttm>              <dttm>              <dttm>              <chr>
#> 1 P01     2020-01-02 12:00:00 2020-01-01 12:00:00 2020-03-01 12:00:00 NA   
#> 2 P02     2020-01-01 00:00:00 2020-01-01 12:00:00 2020-03-01 12:00:00 PRE  
#> 3 P03     2019-12-31 00:00:00 2020-01-01 12:00:00 2020-03-01 12:00:00 NA   
#> # … with 1 more variable: ONTRTFL <chr>

advs <- tribble(
  ~USUBJID, ~ASTDT,            ~TRTSDT,           ~TRTEDT,           ~AENDT,
  "P01",    ymd("2020-03-15"), ymd("2020-01-01"), ymd("2020-03-01"), ymd("2020-12-01"),
  "P02",    ymd("2019-04-30"), ymd("2020-01-01"), ymd("2020-03-01"), ymd("2020-03-15"),
  "P03",    ymd("2019-04-30"), ymd("2020-01-01"), ymd("2020-03-01"), NA,
)
derive_var_ontrtfl(
  advs,
  start_date = ASTDT,
  end_date = AENDT,
  ref_start_date = TRTSDT,
  ref_end_date = TRTEDT,
  ref_end_window = 60,
  span_period = "Y"
)
#> # A tibble: 3 x 6
#>   USUBJID ASTDT      TRTSDT     TRTEDT     AENDT      ONTRTFL
#>   <chr>   <date>     <date>     <date>     <date>     <chr>  
#> 1 P01     2020-03-15 2020-01-01 2020-03-01 2020-12-01 Y      
#> 2 P02     2019-04-30 2020-01-01 2020-03-01 2020-03-15 Y      
#> 3 P03     2019-04-30 2020-01-01 2020-03-01 NA         Y      

advs <- tribble(
  ~USUBJID, ~ASTDT,            ~AP01SDT,          ~AP01EDT,          ~AENDT,
  "P01",    ymd("2020-03-15"), ymd("2020-01-01"), ymd("2020-03-01"), ymd("2020-12-01"),
  "P02",    ymd("2019-04-30"), ymd("2020-01-01"), ymd("2020-03-01"), ymd("2020-03-15"),
  "P03",    ymd("2019-04-30"), ymd("2020-01-01"), ymd("2020-03-01"), NA,
)
derive_var_ontrtfl(
  advs,
  new_var = ONTR01FL,
  start_date = ASTDT,
  end_date = AENDT,
  ref_start_date = AP01SDT,
  ref_end_date = AP01EDT,
  span_period = "Y"
)
#> # A tibble: 3 x 6
#>   USUBJID ASTDT      AP01SDT    AP01EDT    AENDT      ONTR01FL
#>   <chr>   <date>     <date>     <date>     <date>     <chr>   
#> 1 P01     2020-03-15 2020-01-01 2020-03-01 2020-12-01 NA      
#> 2 P02     2019-04-30 2020-01-01 2020-03-01 2020-03-15 Y       
#> 3 P03     2019-04-30 2020-01-01 2020-03-01 NA         Y