# Legend Customization in AE Proportion Difference Visualizations

    library(forestly)
    library(metalite)

The interactive AE forest plots include AE-specific tables presenting numerical values for AE proportions, differences, and confidence intervals (CI), alongside their visualizations. Directly below the column visualizing the AE proportion difference, a legend is displayed. By default, this legend reads: “Treatment <- Favor -> Placebo”. In this vignette, we demonstrate how to customize this legend.

# 1 Step 1: build your metadata

Building interactive AE forest plots starts with constructing the metadata. The detailed procedure for building metadata is covered in the vignette Generate Interactive AE Forest Plots with Drill Down to AE Listing. Therefore, in this vignette, we will skip those details and directly use the metadata created there.

    adsl <- forestly_adsl
    adae <- forestly_adae

    adsl$TRTA <- factor(forestly_adsl$TRT01A,
      levels = c("Xanomeline Low Dose", "Placebo"),
      labels = c("Low Dose", "Placebo")
    )
    adae$TRTA <- factor(forestly_adae$TRTA,
      levels = c("Xanomeline Low Dose", "Placebo"),
      labels = c("Low Dose", "Placebo")
    )

    meta <- meta_adam(population = adsl, observation = adae) |>
      define_plan(plan = plan(
        analysis = "ae_forestly",
        population = "apat",
        observation = "apat",
        parameter = "any;drug-related"
      )) |>
      define_analysis(name = "ae_forestly", label = "Interactive Forest Plot") |>
      define_population(
        name = "apat", group = "TRTA", id = "USUBJID",
        subset = SAFFL == "Y", label = "All Patient as Treated"
      ) |>
      define_observation(
        name = "apat", group = "TRTA",
        subset = SAFFL == "Y", label = "All Patient as Treated"
      ) |>
      define_parameter(
        name = "any",
        subset = NULL,
        label = "Any AEs",
        var = "AEDECOD", soc = "AEBODSYS"
      ) |>
      define_parameter(
        name = "drug-related",
        subset = toupper(AREL) == "RELATED",
        label = "Drug-related AEs",
        var = "AEDECOD", soc = "AEBODSYS"
      ) |>
      meta_build()

# 2 Step 2: customize the legend below the column of AE proportions differences

Users can modify the legend for the AE proportion difference by specifying the `diff_label = ...` argument within the `format_ae_forestly()` function. The default setting is `diff_label = "Treatment <- Favor -> Placebo"`.

In the example below, we show how to change the legend text. We encourage users to tailor this label to best reflect the context of their specific study.

    meta |>
      prepare_ae_forestly() |>
      format_ae_forestly(diff_label = "New Drug <- Favor -> SoC", ) |>
      ae_forestly()

AE Criteria
Incidence (%) in One or More Treatment Groups