coxphms.object: Multi-state Proportional Hazards Regression Object
In survival: Survival Analysis

coxphms.object

R Documentation

Multi-state Proportional Hazards Regression Object

Description

This class of objects is returned by the coxph class of functions to represent a fitted hazards model, when the model has multiple states. The object inherits from the coxph class.

Components

The object has all the components of a coxph object, with the following additions and variations.

states: a character vector listing the states in the model
cmap: the coefficient map. A matrix containing a column for each transition and a row for each coefficient, the value maps that transition/coefficient pair to a position in the coefficient vector. If a particular covariate is not used by a transition the matrix will contain a zero in that position, if two transitions share a coefficient the matrix will contain repeats.
smap: the stratum map. The row labeled ‘(Baseline)’ identifies transitions that do or do not share a baseline hazard. Further rows correspond to strata() terms in the model, each of which may apply to some transitions and not others.
rmap: mapping for the residuals and linear predictors. A two column matrix with one row for each element of the vectors and two columns, the first contains the data row and the second the transition.

Details

In a multi-state model a set of intermediate observations is created during the computation, with a separate set of data rows for each transition. An observation (id and time interval) that is at risk for more than one transition will for instance have a linear predictor and residual for each of the potential transitions. As a result the vector of linear predictors will be longer than the number of observations. The rmap matrix shows the mapping.