Generate clone censor weights (CCW) on the long data.frame

Currently, the only way to generate weights is via multivariable Cox, as described in Maringe et al. 2020

generate_ccw(df, predvars)

Arguments

df

A data.frame with one row per clone per observation period as returned by cast_clones_to_long()

predvars

The variables that will be used to derive weights (subset of those in your data.frame originally). At least one covariate must be used.

Value

The same data.frame with weights added.

References

Maringe, Camille, et al. "Reflection on modern methods: trial emulation in the presence of immortal-time bias. Assessing the benefit of major surgery for elderly lung cancer patients using observational data." International journal of epidemiology 49.5 (2020): 1719-1729.

Examples

# Load the toy dataset
data(toy_df)

# Create clones
clones <- create_clones(toy_df, 
                        id = "id", 
                        event = "death", 
                        time_to_event = "fup_obs", 
                        exposure = "surgery", 
                        time_to_exposure = "timetosurgery", 
                        ced_window = 365.25/2)

clones_long <- cast_clones_to_long(clones)
clones_long_w <- generate_ccw(clones_long, predvars = c("age"))