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Average Hazard (one sample)

ah1.Rd

Calculates the average hazard with survival weight and the corresponding asymptotic confidence interval for a single sample.

Usage

ah1(time, status, tau, conf.int=0.95)

Arguments

time

A numeric vector of follow-up times for right-censored data.

status

A numeric vector indicating the event status; 1 = event occurred, 0 = right censored.

tau

A scalar specifying the end time point (tau) for calculating the average hazard. If tau = NULL, the default is the maximum time point at which the risk set size in both groups is at least 10.

conf.int

A numeric value specifying the confidence level for confidence intervals. The default is 0.95.

Value

An object of class ah1, which contains the following components:

need_stop

Logical indicator. If TRUE, specify another tau. The survival probability at the specified tau needs to be > 0.

tau

The truncation time point used in the analysis.

result1

Estimated average hazard.

Details

It also provides the log-transformed t-year event rate and restricted mean survival time (RMST) along with their variances as intermediate products. Note that the confidence intervals for the t-year event rate and RMST are based on log-scale values. As a result, the confidence intervals may differ slightly from those generated by the surv2sampleComp or survRM2 packages.

References

Uno H and Horiguchi M. Ratio and difference of average hazard with survival weight: new measures to quantify survival benefit of new therapy. Statistics in Medicine. 2023;1-17. <doi:10.1002/sim.9651>

Author

Hajime Uno, Miki Horiguchi

Examples

#====================================================================
# cm214_pfs: The sample reconstructed data of the CheckMate214 study.
# The code below reproduces the results reported by
# Uno and Horiguchi (StatMed; 2023) in Table 6.
#====================================================================
D      = cm214_pfs
time   = D$time
status = D$status
tau    = 21

b = ah1(time=time, status=status, tau=tau, conf.int=0.95)
print(b)
#> $need_stop
#> [1] FALSE
#> 
#> $tau
#> [1] 21
#> 
#> $result1
#>             log(Est) SE(log(Est)) log(low_95) log(upp_95)         Est
#> F(tau)    -0.4215057   0.03017022  -0.4806382  -0.3623731  0.65605827
#> RMST(tau)  2.4576935   0.02548380   2.4077462   2.5076408 11.67784538
#> AH(tau)   -2.8791992   0.05286051  -2.9828039  -2.7755945  0.05617974
#>                low_95      upp_95
#> F(tau)     0.61838860  0.69602261
#> RMST(tau) 11.10889522 12.27593472
#> AH(tau)    0.05065062  0.06231242
#> 
#> attr(,"class")
#> [1] "ah1"
#> attr(,"v_F")
#> [1] 0.770975
#> attr(,"v_R")
#> [1] 0.5500622
#> attr(,"v_Q")
#> [1] 2.366716
#> attr(,"v_U")
#> [1] 0.007469741