Split function to configure risk difference column

Source: R/riskdiff.R

[Stable]

Wrapper function for rtables::add_combo_levels() which configures settings for the risk difference column to be added to an rtables object. To add a risk difference column to a table, this function should be used as split_fun in calls to rtables::split_cols_by(), followed by setting argument riskdiff to TRUE in all following analyze function calls.

add_riskdiff(
  arm_x,
  arm_y,
  col_label = paste0("Risk Difference (%) (95% CI)", if (length(arm_y) > 1)
    paste0("\n", arm_x, " vs. ", arm_y)),
  pct = TRUE
)

Arguments

arm_x

(string)
name of reference arm to use in risk difference calculations.

arm_y

(character)
names of one or more arms to compare to reference arm in risk difference calculations. A new column will be added for each value of arm_y.

col_label

(character)
labels to use when rendering the risk difference column within the table. If more than one comparison arm is specified in arm_y, default labels will specify which two arms are being compared (reference arm vs. comparison arm).

pct

(flag)
whether output should be returned as percentages. Defaults to TRUE.

Value

A closure suitable for use as a split function (split_fun) within rtables::split_cols_by() when creating a table layout.

See also

stat_propdiff_ci() for details on risk difference calculation.

Examples

adae <- tern_ex_adae
adae$AESEV <- factor(adae$AESEV)

lyt <- basic_table() %>%
  split_cols_by("ARMCD", split_fun = add_riskdiff(arm_x = "ARM A", arm_y = c("ARM B", "ARM C"))) %>%
  count_occurrences_by_grade(
    var = "AESEV",
    riskdiff = TRUE
  )

tbl <- build_table(lyt, df = adae)
tbl
#>                                                   Risk Difference (%) (95% CI)   Risk Difference (%) (95% CI)
#>              ARM A        ARM B        ARM C            ARM A vs. ARM B                ARM A vs. ARM C       
#> —————————————————————————————————————————————————————————————————————————————————————————————————————————————
#> MILD        6 (3.0%)     4 (2.3%)     2 (1.2%)          0.7 (-2.5 - 3.9)               1.7 (-1.2 - 4.6)      
#> MODERATE   19 (9.4%)    15 (8.5%)    14 (8.6%)          0.9 (-4.8 - 6.7)               0.8 (-5.1 - 6.7)      
#> SEVERE     34 (16.8%)   38 (21.5%)   32 (19.8%)        -4.6 (-12.6 - 3.3)             -2.9 (-10.9 - 5.1)