Calculate optimal data cutoff that best separates survival curves

Uses stats::optim with the Brent method to test multiple cutoffs and to find the minimum log-rank p-value.

Usage

optimalSurvivalCutoff(
  clinical,
  data,
  censoring,
  event,
  timeStart,
  timeStop = NULL,
  followup = "days_to_last_followup",
  session = NULL,
  filter = TRUE,
  survTime = NULL,
  lower = NULL,
  upper = NULL
)

Arguments

clinical

Data frame: clinical data

data

Numeric: data values

censoring

Character: censor using left, right, interval or interval2

event

Character: name of column containing time of the event of interest

timeStart

Character: name of column containing starting time of the interval or follow up time

timeStop

Character: name of column containing ending time of the interval (only relevant for interval censoring)

followup

Character: name of column containing follow up time

session

Shiny session (only used for the visual interface)

filter

Boolean or numeric: elements to use (all are used by default)

survTime

survTime object: times to follow up, time start, time stop and event (optional)

lower, upper

Bounds in which to search (if NULL, bounds are set to lower = 0 and upper = 1 if all data values are within that interval; otherwise, lower = min(data, na.rm = TRUE) and upper = max(data, na.rm = TRUE))

Value

List containing the optimal cutoff (par) and the corresponding p-value (value)

See also

Other functions to analyse survival: assignValuePerSubject(), getAttributesTime(), labelBasedOnCutoff(), plotSurvivalCurves(), plotSurvivalPvaluesByCutoff(), processSurvTerms(), survdiffTerms(), survfit.survTerms(), testSurvival()

Examples

clinical <- read.table(text = "2549   NA ii  female
                                840   NA i   female
                                 NA 1204 iv    male
                                 NA  383 iv  female
                               1293   NA iii   male
                                 NA 1355 ii    male")
names(clinical) <- c("patient.days_to_last_followup",
                     "patient.days_to_death",
                     "patient.stage_event.pathologic_stage",
                     "patient.gender")
timeStart  <- "days_to_death"
event      <- "days_to_death"

psi <- c(0.1, 0.2, 0.9, 1, 0.2, 0.6)
opt <- optimalSurvivalCutoff(clinical, psi, "right", event, timeStart)