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Kaplan–Meier plot from a Surv object

Source: R/plot_survival_curves.R
plot_survival_curves.Rd

Plot a Kaplan–Meier curve (with confidence intervals and risk table) using a supplied Surv object. If the grouping variable has exactly two levels the function fits a Cox model and annotates hazard ratio (95% CI) and p-value; if more than two groups it displays only the log‑rank p-value.

Usage

plot_survival_curves(
  surv_obj,
  data,
  group_var = "met_exercise_guidelines",
  time_limits = NULL,
  x_breaks = NULL,
  annotate_y = 0.99,
  annotate_x = NULL,
  x_label = "Time (units??)",
  y_label = NULL,
  title = NULL,
  custom_hr_pvalue_text = NULL,
  type = c("survival", "risk")
)

Arguments

surv_obj

A Surv object (can be right‑censored or left‑truncated).

data

A data frame containing the variables referenced by surv_obj and group_var.

group_var

Character, name of the grouping column in data.

time_limits

Numeric(2), x-axis limits for the plot (default c(50, 100)).

x_breaks

Numeric, breaks for the x axis.

annotate_y

Numeric, y position for the annotation text (default 0.99).

annotate_x

Numeric or NULL, x position for annotation; if NULL uses rightmost time_limits.

x_label

Character, label for the x axis (default \"Time\").

y_label

Character, label for the y axis (default \"Probability Event-free\").

title

Character or NULL, plot title (default NULL).

custom_hr_pvalue_text

Character or NULL; if provided, this string will be used for the annotation instead of the automatically computed HR/p-value (for two groups) or log‑rank p-value (for >2 groups).

type

Character, one of "survival" or "risk"; passed to ggsurvfit(). If "survival" the default y_label is "Probability Event-Free"; if "risk" the default y_label is "Probability of Event".

Value

A ggplot object (ggsurvfit).

Examples

data(cancer, package = "survival")

# Example with two groups
lung$sex <- factor(lung$sex, labels = c("Male", "Female"))
surv_obj <- with(lung, survival::Surv(time, status == 2))
plot_survival_curves(surv_obj, lung, group_var = "sex")


# Example with more than two groups
lung$ph.ecog[lung$ph.ecog == 3] <- NA
lung$ph.ecog <- factor(lung$ph.ecog)
surv_obj <- with(lung, survival::Surv(time, status == 2))
plot_survival_curves(surv_obj, lung, group_var = "ph.ecog")


# Cumulative incidence plot
plot_survival_curves(surv_obj, lung, group_var = "ph.ecog")