Create the EPOCH variable

Utilizes the EPOCH method from the SDTM spec: Missing when --DTC is blank; equal to 'SCREENING' if --DTC if before RFXSTDTC; equal to 'TREATMENT' if --DTC is on or after RFXSTDTC and on or before RFXENDTC; equal to 'FOLLOW-UP' if --DTC is after RFXENDTC.

Usage

create_EPOCH(tbl, date_col, RFXSTDTC = "RFXSTDTC", RFXENDTC = "RFXENDTC")

Arguments

tbl

a data frame with date class columns RFXSTDTC and RFXENDTC and the column given in the date_col argument

date_col

a string, the column name of the event date used to determine the EPOCH; this column can either have a date class or a character class in the YYYY-MM-DD format

RFXSTDTC

a string, the date column to use for RFXSTDTC, default is "RFXSTDTC"; this column can either have a date class or a character class in the YYYY-MM-DD format

RFXENDTC

a string, the date column to use for RFXENDTC, default is "RFXENDTC"; this column can either have a date class or a character class in the YYYY-MM-DD format

Value

a modified copy of tbl with the EPOCH column

See also

create_BLFL(), calc_DY()

Examples

df <- data.frame(
  DTC = c("2023-08-01", "2023-08-02", "2023-08-03", "2023-08-04"),
  RFXSTDTC = rep("2023-08-02", 4),
  RFXENDTC = rep("2023-08-03", 4)
)
create_EPOCH(df, date_col = "DTC")
#>          DTC   RFXSTDTC   RFXENDTC     EPOCH
#> 1 2023-08-01 2023-08-02 2023-08-03 SCREENING
#> 2 2023-08-02 2023-08-02 2023-08-03 TREATMENT
#> 3 2023-08-03 2023-08-02 2023-08-03 TREATMENT
#> 4 2023-08-04 2023-08-02 2023-08-03 FOLLOW-UP