Sample Survival Difference (Life-Gained) Data

Computes a group-vs-group survival difference curve and confidence interval, matching the output of the HAZDIFL macro used in tp.hp.dead.life-gained.sas.

Usage

sample_survival_difference_data(
  n = 500,
  time_max = 10,
  n_points = 500,
  groups = c(Control = 1, Treatment = 0.7),
  shape = 1.5,
  scale = 8,
  ci_level = 0.95,
  seed = 42L
)

Arguments

n

Number of patients per group (used for CI width). Default 500.

time_max

Upper end of the time axis (years). Default 10.

n_points

Number of prediction grid points. Default 500.

groups

Named numeric vector of length 2; hazard multipliers for groups 1 and 2. The group with the smaller multiplier has better survival. Default c("Control" = 1.0, "Treatment" = 0.7).

shape

Weibull shape. Default 1.5.

scale

Weibull scale (years). Default 8.0.

ci_level

Confidence level. Default 0.95.

seed

Random seed. Default 42.

Value

A data frame with columns time, difference, diff_lower, diff_upper, group1_surv, group2_surv.

Details

SAS column mapping:

• time ← prediction grid

• difference ← survival(group 2) - survival(group 1) (percentage points)

• diff_lower ← lower CI on difference

• diff_upper ← upper CI on difference

• group1_surv ← survival curve for group 1

• group2_surv ← survival curve for group 2

See also

hv_survival_difference(), sample_hazard_data()

Examples

diff_dat <- sample_survival_difference_data(
  groups = c("Control" = 1.0, "Treatment" = 0.7)
)
head(diff_dat)
#>         time  difference  diff_lower diff_upper group1_surv group2_surv
#> 1 0.01000000 0.001831068 -0.03739885 0.04106099    99.99558    99.99741
#> 2 0.03002004 0.009522643 -0.08737593 0.10642122    99.97702    99.98654
#> 3 0.05004008 0.020489267 -0.13072627 0.17170481    99.95054    99.97103
#> 4 0.07006012 0.033934691 -0.17121839 0.23908777    99.91808    99.95201
#> 5 0.09008016 0.049459769 -0.21006489 0.30898443    99.88059    99.93005
#> 6 0.11010020 0.066810699 -0.24784775 0.38146915    99.83868    99.90549