cutoff_adjustment {biostatUZH}R Documentation

Calculated adjusted p-value and adjusted hazard ratio when using minimal p-value approach.

Description

Adjustement of the p-value is done according to Hilsenbeck & Clark 1996 "Practical p-value adjustment for optimally selected cutpoints". Adjustment of the hazard ratio is done via the heuristic shrinkage proposed by van Houwelingen and Le Cessie "Predictive value of statistical models", 1990, Statistics in medicine / Schumacher et al. 2012, pp. 424f..

Usage

cutoff_adjustment(time, time2, event, outcome, trim = 2,
                  na.omit = FALSE, data, firth = FALSE, reverse = FALSE)

Arguments

time

A character string, corresponds to 'time' from survival::Surv

time2

A character string, corresponds to 'time2' from survival::Surv

event

A character string, corresponds to 'event' from survival::Surv

outcome

A character string for the continuous outcome variable.

trim

Number of events that should be excluded on the lower and upper end to avoid complete separation.

na.omit

Logical value. If TRUE, rows with missing values will be excluded. Default is FALSE.

data

Data frame.

firth

Logical value. If TRUE, then Firth Cox-Regression will be used. Default is FALSE. Package "coxphf" must be installed.

reverse

Logical value. If TRUE, then the event variable will be switched within the cox regression. Default is FALSE.

Value

n.event

Number of events.

meas.event

Values of variable outcome associated with events.

bound.l

Lower bound of truncation, i.e. smallest value considered after trim.

bound.u

upper bound of truncation, i.e. largest value considered after trim.

meas.event.trunc

Truncated set of values of covariates.

cutpoints

Set of cutpoints used in the minimal p-value approach.

p.unadj.min

Minimal p-value.

cutoff

Estimated cut-off value.

p.adj

Adjusted p-value.

c.hat

Estimated shrinkage coefficient.

beta.adj

Adjusted beta coefficient. Direction depends on argument "reverse".

ci.beta.adj

95% confidence interval for the adjusted beta coefficient. Direction depends on argument "reverse".

hr.adj

Adjusted hazard ratio. Direction depends on argument "reverse".

ci.hr.adj

95% confidence interval for the adjusted hazard ratio. Direction depends on argument "reverse".

Author(s)

Niels Hagenbuch, Klaus Steigmiller

See Also

Houwelingen and Le Cessie "Predictive value of statistical models", 1990, Statistics in medicine / Schumacher et al. 2012, pp. 424f in "Handbook of statistics in clinical oncology" / Hilsenbeck & Clark 1996 "Practical p-value adjustment for optimally selected cutpoints"

Examples

## Not run: 
cutoff_adjustment(time = "time.num", time2 = "end.time", event = "event", 
                  na.omit = TRUE,
                  outcome = "lactat", trim = 2,
                  data = ddsurv, 
                  firth = FALSE, reverse = TRUE)

## End(Not run)

[Package biostatUZH version 1.8.0 Index]