lrstat (version 0.2.13)

patrisk: Probability of Being at Risk

Description

Obtains the probability of being at risk at given analysis times.

Usage

patrisk(
  time = NA_real_,
  piecewiseSurvivalTime = 0L,
  lambda = NA_real_,
  gamma = 0L
)

Value

A vector of probabilities of being at risk at the specified analysis times after enrollment for a patient in a treatment group with specified piecewise exponential survival and dropout distributions.

Arguments

time

A vector of analysis times at which to calculate the probability of being at risk.

piecewiseSurvivalTime

A vector that specifies the starting time of piecewise exponential survival time intervals. Must start with 0, e.g., c(0, 6) breaks the time axis into 2 event intervals: [0, 6) and [6, Inf). Defaults to 0 for exponential distribution.

lambda

A vector of hazard rates for the event. One for each analysis time interval.

gamma

The hazard rate for exponential dropout, or a vector of hazard rates for piecewise exponential dropout.

Author

Kaifeng Lu,

Examples

# Piecewise exponential survival with hazard 0.0533 in the first 6
# months, and hazard 0.0309 thereafter, and 5% dropout by the end of
# 1 year.

patrisk(time = c(3, 9), piecewiseSurvivalTime = c(0, 6),
        lambda = c(0.0533, 0.0309), gamma = -log(1-0.05)/12)