Generate hazard ratio with prediction intervals from parametric bootstrap simulation

Usage

calc_ave_hr_pi(
  sim,
  trt,
  group = NULL,
  pi.range = 0.95,
  calc.obs = TRUE,
  trt.assign = c("default", "reverse"),
  simtimelast = NULL,
  boot.subj = TRUE
)

calc_hr_pi(
  sim,
  trt,
  group = NULL,
  pi.range = 0.95,
  calc.obs = TRUE,
  trt.assign = c("default", "reverse")
)

Arguments

sim: A survparamsim class object generated by surv_param_sim() function.
trt: A string to specify which column define treatment status to calculate HR.
group: Optional string(s) to specify grouping variable(s). You will have faceted histograms for these variables in plot_hr_pi() function.
pi.range: Prediction interval for simulated HR.
calc.obs: A logical to specify whether to calculate HR for the observed data. Need be set as FALSE if survival information in the newdata is dummy.
trt.assign: Specify which of the categories of trt need to be considered as control group. See details below if you have more than two categories.
simtimelast: An optional numeric to specify duration for average HR calculation. If NULL (default), the last observation time in the newdata will be used.
boot.subj: Boolean to specify whether bootstrapping of subjects are performed before calculating HR. Default TRUE.

Details

calc_hr_pi() calculate hazard ratio using the simulated survival times with Cox proportional hazard model, while calc_ave_hr_pi() calculate "average" hazard ratio using the mean survival & probability density function per treatment groups.

If your trt has more than two categories/levels and want to specify which one to use as a reference group, you can convert the column into a factor in the newdata input for surv_param_sim(). The first level will be used as a reference group.