kmdiff function

Estimate of Milestone Survival Difference

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

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.

Returns

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.

Examples

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

Author(s)

Kaifeng Lu, kaifenglu@gmail.com