plot.SurvSurv: Provides plots of trial- and individual-level surrogacy in the Information-Theoretic framework when both S and T are time-to-event endpoints

Description

Produces plots that provide a graphical representation of trial- and/or individual-level surrogacy (R2_ht and R2_hInd per cluster) based on the Information-Theoretic approach of Alonso & Molenberghs (2007).

Usage

# S3 method for SurvSurv
plot(x, Trial.Level=TRUE, Weighted=TRUE, 
Indiv.Level.By.Trial=TRUE, Xlab.Indiv, Ylab.Indiv, Xlab.Trial, 
Ylab.Trial, Main.Trial, Main.Indiv, 
Par=par(oma=c(0, 0, 0, 0), mar=c(5.1, 4.1, 4.1, 2.1)), ...)

Arguments

x: An object of class FixedBinBinIT.
Trial.Level: Logical. If Trial.Level=TRUE, a plot of the trial-specific treatment effects on the true endpoint against the trial-specific treatment effect on the surrogate endpoints is provided (as a graphical representation of \(R_{ht}\)). Default TRUE.
Weighted: Logical. This argument only has effect when the user requests a trial-level surrogacy plot (i.e., when Trial.Level=TRUE in the function call). If Weighted=TRUE, the circles that depict the trial-specific treatment effects on the true endpoint against the surrogate endpoint are proportional to the number of patients in the trial. If Weighted=FALSE, all circles have the same size. Default TRUE.
Indiv.Level.By.Trial: Logical. If Indiv.Level.By.Trial=TRUE, a plot that shows the estimated \(R^2_{h.ind}\) for each trial (and confidence intervals) is provided. Default TRUE.
Xlab.Indiv: The legend of the X-axis of the plot that depicts the estimated \(R^2_{h.ind}\) per trial. Default "\(R[h.ind]^{2}\).
Ylab.Indiv: The legend of the Y-axis of the plot that shows the estimated \(R^2_{h.ind}\) per trial. Default "Trial".
Xlab.Trial: The legend of the X-axis of the plot that depicts trial-level surrogacy. Default "Treatment effect on the surrogate endpoint (\(\alpha_{i}\))".
Ylab.Trial: The legend of the Y-axis of the plot that depicts trial-level surrogacy. Default "Treatment effect on the true endpoint (\(\beta_{i}\))".
Main.Indiv: The title of the plot that depicts individual-level surrogacy. Default "Individual-level surrogacy".
Main.Trial: The title of the plot that depicts trial-level surrogacy. Default "Trial-level surrogacy".
Par: Graphical parameters for the plot. Default par(oma=c(0, 0, 0, 0), mar=c(5.1, 4.1, 4.1, 2.1)).
...: Extra graphical parameters to be passed to plot().

Author

Wim Van der Elst, Ariel Alonso, & Geert Molenberghs

References

Alonso, A, & Molenberghs, G. (2007). Surrogate marker evaluation from an information theory perspective. Biometrics, 63, 180-186.

Examples

Run this code

# Open Ovarian dataset
data(Ovarian)

# Conduct analysis
Fit <- SurvSurv(Dataset = Ovarian, Surr = Pfs, SurrCens = PfsInd,
True = Surv, TrueCens = SurvInd, Treat = Treat, 
Trial.ID = Center, Alpha=.05)

# Examine results 
summary(Fit)
plot(Fit, Trial.Level = FALSE, Indiv.Level.By.Trial=TRUE)
plot(Fit, Trial.Level = TRUE, Indiv.Level.By.Trial=FALSE)