A Stata user-written command to check the proportional-hazards assumption after a Cox model using restricted cubic splines
stphcoxrcs checks the proportional-hazards assumption for one covariate of interest (binary or
continuous) after fitting a model with stcox. In particular, stphcoxrcs models the natural
logarithm of analysis time using restricted cubic splines transformations, which are interacted with the
covariate specified in varname. A joint Wald (default) or likelihood ratio test of all the
interaction terms is carried out to test the proportional-hazards assumption. Lastly, stphcoxrcs
produces a graph of the time-varying hazard ratio.
To install the last version of stphcoxrcs from GitHub, type
net install stphcoxrcs, from("https://raw.githubusercontent.com/anddis/stphcoxrcs/master/")
from within a web-aware Stata.
Andrea Discacciati, Viktor Oskarsson, and Nicola Orsini
Karolinska Institutet, Sweden