This function nonparametrically estimates the potential cumulative incidence function
using composite variable strategy (competing risks data structure).
This strategy adopts the first occurrence of either the intermediate
or primary event as the event of interest.
surv.composite(A, Time, cstatus, weights = rep(1, length(A)), subset = NULL)
Arguments
- A
Treatment indicator, 1 for treatment and 0 for control.
- Time
Time to event.
- cstatus
Indicator of event, 1 for the primary event, 2 for the intercurrent event, 0 for censoring.
- weights
Weight for each subject.
- subset
Subset, either numerical or logical.
Value
A list including
- time1
Time points in the treated group.
- time0
Time points in the control group.
- cif1
Estimated cumulative incidence function in the treated group.
- cif0
Estimated cumulative incidence function in the control group.
- se1
Standard error of the estimated cumulative incidence function in the treated group.
- se0
Standard error of the estimated cumulative incidence function in the control group.
- time
Time points in both groups.
- ate
Estimated treatment effect (difference in cumulative incidence functions).
- se
Standard error of the estimated treatment effect.
- p.val
P value of testing the treatment effect based on logrank test.
Details
The composite variable strategy addresses the problem of intercurrent events by expanding the
outcome variables. It aggregates the intercurrent event and the primary outcome event into a single
composite outcome variable. The idea is not new in the context of progression-free survival,
where the composite outcome variable is defined as the occurrence of either a non-terminal event
(e.g., cancer progression) or a terminal event (e.g., death). One widely used composite outcome
variable has the form Q(w) = \min\{T(w), R(w)\} for w = 1, 0. When this simple form
is adopted, the difference in counterfactual cumulative incidences is
\tau(t) = P( Q(1) < t ) - P( Q(0) < t ),
representing the difference in probabilities of experiencing either intercurrent events or primary
outcome events during (0,t) under active treatment and placebo.