nbstat1 {lrstat} | R Documentation |
Negative binomial rate ratio by stratum
Description
Obtains the number of subjects accrued, number of events, number of dropouts, number of subjects reaching the maximum follow-up, total exposure, rate and variance for log rate in each group, rate ratio and variance for log rate ratio by stratum at a given calendar time.
Usage
nbstat1(
time = NA_real_,
rateRatioH0 = 1,
allocationRatioPlanned = 1,
accrualTime = 0L,
accrualIntensity = NA_real_,
piecewiseSurvivalTime = 0L,
stratumFraction = 1L,
kappa1 = NA_real_,
kappa2 = NA_real_,
lambda1 = NA_real_,
lambda2 = NA_real_,
gamma1 = 0L,
gamma2 = 0L,
accrualDuration = NA_real_,
followupTime = NA_real_,
fixedFollowup = 0L,
nullVariance = 0L
)
Arguments
time |
The calendar time for data cut. |
rateRatioH0 |
Rate ratio under the null hypothesis. |
allocationRatioPlanned |
Allocation ratio for the active treatment versus control. Defaults to 1 for equal randomization. |
accrualTime |
A vector that specifies the starting time of
piecewise Poisson enrollment time intervals. Must start with 0, e.g.,
|
accrualIntensity |
A vector of accrual intensities. One for each accrual time interval. |
piecewiseSurvivalTime |
A vector that specifies the starting time of
piecewise exponential survival time intervals. Must start with 0, e.g.,
|
stratumFraction |
A vector of stratum fractions that sum to 1. Defaults to 1 for no stratification. |
kappa1 |
The dispersion parameter (reciprocal of the shape parameter of the gamma mixing distribution) for the active treatment group by stratum. |
kappa2 |
The dispersion parameter (reciprocal of the shape parameter of the gamma mixing distribution) for the control group by stratum. |
lambda1 |
The rate parameter of the negative binomial distribution for the active treatment group by stratum. |
lambda2 |
The rate parameter of the negative binomial distribution for the control group by stratum. |
gamma1 |
The hazard rate for exponential dropout, a vector of hazard rates for piecewise exponential dropout applicable for all strata, or a vector of hazard rates for dropout in each analysis time interval by stratum for the active treatment group. |
gamma2 |
The hazard rate for exponential dropout, a vector of hazard rates for piecewise exponential dropout applicable for all strata, or a vector of hazard rates for dropout in each analysis time interval by stratum for the control group. |
accrualDuration |
Duration of the enrollment period. |
followupTime |
Follow-up time for the last enrolled subject. |
fixedFollowup |
Whether a fixed follow-up design is used. Defaults to 0 for variable follow-up. |
nullVariance |
Whether to calculate the variance for log rate ratio under the null hypothesis. |
Value
A list with two components:
-
resultsUnderH1
: A data frame containing the following variables:-
stratum
: The stratum. -
time
: The calendar time since trial start. -
subjects
: The number of enrolled subjects. -
nevents
: The total number of events. -
nevents1
: The number of events in the active treatment group. -
nevents2
: The number of events in the control group. -
ndropouts
: The total number of dropouts. -
ndropouts1
: The number of dropouts in the active treatment group. -
ndropouts2
: The number of dropouts in the control group. -
nfmax
: The total number of subjects reaching maximum follow-up. -
nfmax1
: The number of subjects reaching maximum follow-up in the active treatment group. -
nfmax2
: The number of subjects reaching maximum follow-up in the control group. -
exposure
: The total exposure time. -
exposure1
: The exposure time for the active treatment group. -
exposure2
: The exposure time for the control group. -
rateRatio
: The rate ratio of the active treatment group versus the control group. -
vlogRate1
: The variance for the log rate parameter for the active treatment group. -
vlogRate2
: The variance for the log rate parameter for the control group. -
vlogRR
: The variance of log rate ratio.
-
-
resultsUnderH0
whennullVariance = TRUE
: A data frame with the following variables:-
stratum
: The stratum. -
time
: The analysis time since trial start. -
lambda1H0
: The restricted maximum likelihood estimate of the event rate for the active treatment group. -
lambda2H0
: The restricted maximum likelihood estimate of the event rate for the control group. -
rateRatioH0
: The rate ratio under H0. -
vlogRate1H0
: The variance for the log rate parameter for the active treatment group under H0. -
vlogRate2H0
: The variance for the log rate parameter for the control group under H0. -
vlogRRH0
: The variance of log rate ratio under H0. -
lambda1
: The true event rate for the active treatment group. -
lambda2
: The true event rate for the control group. -
rateRatio
: The true rate ratio.
-
-
resultsUnderH0
whennullVariance = FALSE
: A data frame with the following variables:-
stratum
: The stratum. -
time
: The analysis time since trial start. -
rateRatioH0
: The rate ratio under H0. -
lambda1
: The true event rate for the active treatment group. -
lambda2
: The true event rate for the control group. -
rateRatio
: The true rate ratio.
-
Author(s)
Kaifeng Lu, kaifenglu@gmail.com
Examples
# Example 1: Variable follow-up design
nbstat1(time = 2,
accrualIntensity = 1956/1.25,
kappa1 = 5,
kappa2 = 5,
lambda1 = 0.7*0.125,
lambda2 = 0.125,
gamma1 = 0,
gamma2 = 0,
accrualDuration = 1.25,
followupTime = 2.75)
# Example 2: Fixed follow-up design
nbstat1(time = 1.8,
accrualIntensity = 220/1.5,
stratumFraction = c(0.2, 0.8),
kappa1 = 3,
kappa2 = 3,
lambda1 = c(0.5*8.4, 0.7*10.2),
lambda2 = c(8.4, 10.2),
gamma1 = 0.05,
gamma2 = 0.05,
accrualDuration = 1.5,
followupTime = 0.5,
fixedFollowup = 1,
nullVariance = 1)