Number of Enrolled Subjects — accrual • lrstat

Obtains the number of subjects enrolled by given calendar times.

Usage

accrual(time, accrualTime, accrualIntensity, accrualDuration)

Arguments

time: A vector of calendar times at which to calculate the number of enrolled subjects.
accrualTime: A vector that specifies the starting time of piecewise Poisson enrollment time intervals. Must start with 0, e.g., c(0, 3) breaks the time axis into 2 accrual intervals: \([0, 3)\) and \([3, \infty)\).
accrualIntensity: A vector of accrual intensities. One for each accrual time interval.
accrualDuration: Duration of the enrollment period.

Value

A vector of total number of subjects enrolled by the specified calendar times.

Author

Kaifeng Lu, kaifenglu@gmail.com

Examples

# Example 1: Uniform enrollment with 20 patients per month for 12 months.

accrual(time = 3, accrualTime = 0, accrualIntensity = 20,
        accrualDuration = 12)
#> [1] 60


# Example 2: Piecewise accrual, 10 patients per month for the first
# 3 months, and 20 patients per month thereafter. Patient recruitment
# ends at 12 months for the study.

accrual(time = c(2, 9), accrualTime = c(0, 3),
        accrualIntensity = c(10, 20), accrualDuration = 12)
#> [1]  20 150