calc_rmd: Calculate restricted mean durations

In psm3mkv: Evaluate Partitioned Survival and State Transition Models

Calculate restricted mean durations

Description

Calculates the restricted mean duration, given the form of a parametric distribution of Royston-Parmar splines

Usage

calc_rmd(Tw, type = NA, spec = NA, survobj = NULL)

Arguments

Tw	is the time horizon (weeks) over which the mean should be calculated.
type	is either "par" for regular parametric form (exponential, weibull etc) or "spl" for Royston-Parmar splines.
spec	is a list comprising: If type=="par": dist is the statistical distribution (named per flexsurv::flexsurvreg) and pars is a vector of the parameters for that distribution. Exponential distribution (exp) requires the rate parameter. Weibull distribution (both weibullPH and weibull formulations) requires the shape and scale parameters. Log-logistic distribution (llogis) requires the shape and scale parameters. Log-normal distribution (lnorm) requires the meanlog and sdlog parameters. Gamma and Gompertz distributions (gamma and gompertz) require the shape and rate parameters. Generalized Gamma requires the mu, sigma and Q parameters if using the standard parameterization (gengamma) or shape, scale and k parameters if using the original parameterization (gengamma.orig). If type=="spl": gamma - Vector of parameters describing the baseline spline function, as described in flexsurv::flexsurvspline. This may be supplied as a vector with number of elements equal to the length of knots, in which case the parameters are common to all times. Alternatively a matrix may be supplied, with rows corresponding to different times, and columns corresponding to knots. knots - Vector of locations of knots on the axis of log time, supplied in increasing order. Unlike in flexsurv::flexsurvspline, these include the two boundary knots. scale - Either "hazard", "odds", or "normal", as described in flexsurv::flexsurvspline. With the default of no knots in addition to the boundaries, this model reduces to the Weibull, log-logistic and log-normal respectively. The scale must be common to all times.
survobj	is a survival fit object from flexsurv::flexsurvspline or flexsurv::flexsurvreg

Value

the restricted mean duration, a numeric value.

Examples

calc_rmd(Tw=200,
    type="spl",
    spec=list(gamma=c(0.1,0.2,0.1), knots=c(-5,2,4), scale="normal")
    )
calc_rmd(Tw=250,
    type="par",
    spec=list(dist="lnorm", pars=c(3,1))
    )

psm3mkv documentation built on June 22, 2024, 10:09 a.m.