Plot incremental outcomes on the cost-effectiveness plane

plot_psa_scatter takes a data.frame of incremental quality-adjusted life-years (QALYs) and incremental costs, as might be obtained from a probabilistic sensitivity analysis, and plots these data on the incremental cost-effectiveness plane.

Usage

plot_psa_scatter(
  data,
  delta_qalys,
  delta_costs,
  currency = "$",
  point_alpha = 0.4,
  point_color = "#0099cc",
  point_shape = 16,
  point_size = 2,
  point_jitter_height = 0,
  point_jitter_width = 0,
  plot_wtp_at = NULL,
  wtp_alpha = 1,
  wtp_color = "#154754",
  wtp_linetype = "dashed",
  wtp_linewidth = 0.5,
  show_mean = TRUE,
  mean_alpha = 1,
  mean_color = "#7a0d66",
  mean_shape = 18,
  mean_size = 3
)

Arguments

data: A data.frame.
delta_qalys: Unquoted column name for incremental QALYs.
delta_costs: Unquoted column name for incremental costs.
currency: String for the currency symbol. Default is $.
point_alpha: Numeric value for point opacity. Default is 0.4.
point_color: Point color. Default is #0099cc.
point_shape: Integer value for point shape. Default is 16. See ?pch for available shapes.
point_size: Numeric value for point size. Default is 2.
point_jitter_height, point_jitter_width: Numeric value for vertical and horizontal jittering. Default is 0 (no jittering). Be careful that some key-outcome pairs may not be plotted if there is too much jitter.
plot_wtp_at: Numeric value at which to plot the WTP threshold. By default, this argument is NULL and the WTP threshold is not plotted.
wtp_alpha: Numeric value for WTP threshold line opacity. Default is 1.
wtp_color: Color for WTP threshold line. Default is #154754.
wtp_linetype: A valid specification of the WTP threshold line type. Default is dashed (2). See the ggplot2 documentation for valid options.
wtp_linewidth: Numeric value for the WTP threshold line width. Default is 0.5.
show_mean: Boolean indicating if the mean of incremental QALYs and costs should be displayed (as a point). Default is TRUE.
mean_alpha: Numeric value for mean point opacity. Default is 1.
mean_color: Color for the mean point. Default is #7a0d66.
mean_shape: Integer value for mean point shape. Default is 18. See ?pch for available shapes.
mean_size: Numeric value for point size. Default is 3.

Value

A ggplot object.

Details

Fore more information on the display of incremental outcomes on the cost-effectiveness plane, see, for example, Fenwick et al., 2006.

Examples

library(ggplot2)
df <- data.frame(
  d_qalys = runif(1000, -1, 2),
  d_costs = runif(1000, -1000, 10000),
  country = rep(c("Country A", "Country B"), each = 500)
)

# Standard plot (without WTP threshold)
plot_psa_scatter(df, d_qalys, d_costs)
#> No WTP threshold is plotted.


# Now with a WTP threshold of 20,000
plot_psa_scatter(df, d_qalys, d_costs, plot_wtp_at = 20000)
#> The WTP threshold is plotted at
#> $20000 per QALY gained.


# Facet plot by adding a call to facet_plot/facet_grid
plot_psa_scatter(df, d_qalys, d_costs, plot_wtp_at = 20000) +
  facet_wrap(vars(country))
#> The WTP threshold is plotted at
#> $20000 per QALY gained.


# Don't forget that column names should be unquoted
if (FALSE) {
plot_psa_scatter(df, "d_qalys", "d_costs")
}