kmdiff: Estimate of Milestone Survival Difference

In lrstat: Power and Sample Size Calculation for Non-Proportional Hazards and Beyond

Estimate of Milestone Survival Difference

Description

Obtains the estimate of milestone survival difference between two treatment groups.

Usage

kmdiff(
  data,
  rep = "",
  stratum = "",
  treat = "treat",
  time = "time",
  event = "event",
  milestone = NA_real_,
  survDiffH0 = 0,
  conflev = 0.95
)

Arguments

data	The input data frame that contains the following variables: rep: The replication for by-group processing. stratum: The stratum. treat: The treatment. time: The possibly right-censored survival time. event: The event indicator.
rep	The name of the replication variable in the input data.
stratum	The name of the stratum variable in the input data.
treat	The name of the treatment variable in the input data.
time	The name of the time variable in the input data.
event	The name of the event variable in the input data.
milestone	The milestone time at which to calculate the survival probability.
survDiffH0	The difference in milestone survival probabilities under the null hypothesis. Defaults to 0 for superiority test.
conflev	The level of the two-sided confidence interval for the difference in milestone survival probabilities. Defaults to 0.95.

Value

A data frame with the following variables:

• rep: The replication.

• milestone: The milestone time relative to randomization.

• survDiffH0: The difference in milestone survival probabilities under the null hypothesis.

• surv1: The estimated milestone survival probability for the treatment group.

• surv2: The estimated milestone survival probability for the control group.

• survDiff: The estimated difference in milestone survival probabilities.

• vsurv1: The variance for surv1.

• vsurv2: The variance for surv2.

• vsurvDiff: The variance for survDiff.

• survDiffZ: The Z-statistic value.

• survDiffPValue: The one-sided p-value.

• lower: The lower bound of confidence interval.

• upper: The upper bound of confidence interval.

• conflev: The level of confidence interval.

Author(s)

Kaifeng Lu, [e-mail]

Examples

df <- kmdiff(data = rawdata, rep = "iterationNumber",
             stratum = "stratum", treat = "treatmentGroup",
             time = "timeUnderObservation", event = "event",
             milestone = 12)
head(df)

lrstat documentation built on Aug. 8, 2025, 7:36 p.m.