Provides a geometric average hazard ratio under various non-proportional hazards assumptions for either single or multiple strata studies. The piecewise exponential distribution allows a simple method to specify a distribution and enrollment pattern where the enrollment, failure and dropout rates changes over time.
Usage
ahr(
enroll_rate = define_enroll_rate(duration = c(2, 2, 10), rate = c(3, 6, 9)),
fail_rate = define_fail_rate(duration = c(3, 100), fail_rate = log(2)/c(9, 18), hr =
c(0.9, 0.6), dropout_rate = 0.001),
total_duration = 30,
ratio = 1
)Arguments
- enroll_rate
An
enroll_ratedata frame with or without stratum created bydefine_enroll_rate().- fail_rate
A
fail_ratedata frame with or without stratum created bydefine_fail_rate().- total_duration
Total follow-up from start of enrollment to data cutoff; this can be a single value or a vector of positive numbers.
- ratio
Ratio of experimental to control randomization.
Value
A data frame with time (from total_duration),
ahr (average hazard ratio), n (sample size), event (expected number of events),
info (information under given scenarios), and info0
(information under related null hypothesis) for each value of
total_duration input.
Examples
# Example 1: default
ahr()
#> time ahr n event info info0
#> 1 30 0.6952153 108 58.49097 14.32724 14.62274
# Example 2: default with multiple analysis times (varying total_duration)
ahr(total_duration = c(15, 30))
#> time ahr n event info info0
#> 1 15 0.7857415 108 30.27841 7.441186 7.569603
#> 2 30 0.6952153 108 58.49097 14.327243 14.622742
# Example 3: stratified population
enroll_rate <- define_enroll_rate(
stratum = c(rep("Low", 2), rep("High", 3)),
duration = c(2, 10, 4, 4, 8),
rate = c(5, 10, 0, 3, 6)
)
fail_rate <- define_fail_rate(
stratum = c(rep("Low", 2), rep("High", 2)),
duration = c(1, Inf, 1, Inf),
fail_rate = c(.1, .2, .3, .4),
dropout_rate = .001,
hr = c(.9, .75, .8, .6)
)
ahr(enroll_rate = enroll_rate, fail_rate = fail_rate, total_duration = c(15, 30))
#> time ahr n event info info0
#> 1 15 0.7332218 164 113.2782 28.18130 28.31954
#> 2 30 0.7175169 170 166.1836 41.49942 41.54590