RMST difference of 2 arms

Usage

rmst(
  data,
  tau = 10,
  var_label_tte = "tte",
  var_label_event = "event",
  var_label_group = "treatment",
  formula = NULL,
  reference = "control",
  alpha = 0.05
)

Arguments

data: A time-to-event dataset with a column tte indicating the survival time and a column of event indicating whether it is event or censor.
tau: RMST analysis time.
var_label_tte: Column name of the TTE variable.
var_label_event: Column name of the event variable.
var_label_group: Column name of the grouping variable.
formula: (default: NULL) A formula that indicates the TTE, event, and group variables using the syntax Surv(tte, event) ~ group) (see Details below for more information). This is an alternative to specifying the variables as strings. If a formula is provided, the values passed to var_label_tte, var_label_event, and var_label_group are ignored.
reference: A group label indicating the reference group.
alpha: Type I error.

Value

The z statistics.

Details

The argument formula is provided as a convenience to easily specify the TTE, event, and grouping variables using the syntax Surv(tte, event) ~ group). Surv() is from the {survival} package (survival::Surv()). You can also explicitly name the arguments passed to Surv(), for example the following is equivalent Surv(event = event, time = tte) ~ group). Note however that the function Surv() is never actually executed. Similarly, any other functions applied in the formula are also ignored, thus you shouldn't apply any transformation functions such as log() since these will have no effect.

Examples

data(ex1_delayed_effect)
rmst(
  data = ex1_delayed_effect,
  var_label_tte = "month",
  var_label_event = "evntd",
  var_label_group = "trt",
  tau = 10,
  reference = "0"
)
#> $method
#> [1] "RMST"
#> 
#> $parameter
#> [1] 10
#> 
#> $estimate
#> [1] 0.8650493
#> 
#> $se
#> [1] 0.3900344
#> 
#> $z
#> [1] 2.21788
#> 

# Formula interface
rmst(
  data = ex1_delayed_effect,
  formula = Surv(month, evntd) ~ trt,
  tau = 10,
  reference = "0"
)
#> $method
#> [1] "RMST"
#> 
#> $parameter
#> [1] 10
#> 
#> $estimate
#> [1] 0.8650493
#> 
#> $se
#> [1] 0.3900344
#> 
#> $z
#> [1] 2.21788
#>