plot_subgroup_effects: Plot Subgroup Analysis Results

Description

Creates diagnostic plots for subgroup treatment effects from df_super object

Usage

plot_subgroup_effects(
  df_super,
  z,
  hrz_crit = 0,
  log.hrs = NULL,
  ahr_empirical = NULL,
  plot_type = c("both", "profile", "ahr"),
  add_rug = TRUE,
  zpoints_by = 1,
  ...
)

Value

A list containing:

cut.zero: The minimum z value where loghr_po < hrz_crit
AHR_opt: Average hazard ratio for optimal subgroup (z >= cut.zero)
zpoints: Grid of z values used for AHR calculations
HR.zpoints: AHR for population with z >= zpoints
HRminus.zpoints: AHR for population with z <= zpoints
HR2.zpoints: Alternative AHR calculation for z >= zpoints
HRminus2.zpoints: Alternative AHR calculation for z <= zpoints

Arguments

df_super: A data frame containing subgroup analysis results with columns: loghr_po (log hazard ratios), and optionally theta_1 and theta_0 (treatment-specific parameters)
z: Character string specifying the column name to use as the subgroup score (e.g., "z_age", "z_size", "subgroup"). Required.
hrz_crit: Critical hazard ratio threshold for defining optimal subgroup. Default is 1 (HR=1 on log scale is 0).
log.hrs: Optional vector of reference log hazard ratios to display as horizontal lines. Default is NULL.
ahr_empirical: Optional empirical average hazard ratio to display. If NULL, calculated from data. Default is NULL.
plot_type: Character string specifying plot type: "both" (default), "profile", or "ahr".
add_rug: Logical indicating whether to add rug plot of z values. Default is TRUE.
zpoints_by: Step size for z-axis grid when calculating AHR curves. Default is 1.
...: Additional graphical parameters passed to plot()

Details

The function creates up to two plots:

Treatment effect profile: Shows log hazard ratio as function of z
Average hazard ratio curve: Shows AHR for subgroups z >= threshold

The "optimal" subgroup is defined as patients with z >= cut.zero, where cut.zero is the minimum z value with favorable treatment effect (loghr < hrz_crit).