R help - Feb 2008 - New Package 'JM' for the Joint Modelling of Longitudinal and Survival Data

Dear R-users,

I'd like to announce the release of the new package JM (JM_0.1-0 
available from CRAN) for the joint modelling of longitudinal and 
time-to-event data.

The package has a single model-fitting function called jointModel(), 
which accepts as main arguments a linear mixed effects object fit 
returned by function lme() of package nlme, and a survival object fit 
returned by either function coxph() or function survreg() of package 
survival. In addition, the method argument of jointModel() specifies 
the type of the survival submodel to be fitted and the type of the 
numerical integration technique; available options are:

    * "ph-GH": the time-dependent version of a proportional hazards 
model with unspecified baseline hazard function. This option 
corresponds to the joint model proposed by Wulfsohn and Tsiatis, 
Biometrics, 1997.

    * "weibull-GH": the Weibull model under the accelerated failure 
time formulation.

    * "ch-GH" and "ch-Laplace": an additive log cumulative
hazard
model, in which the log cumulative baseline hazard is approximated 
using B-splines.

For "ph-GH", "weibull-GH" and "ch-GH" the
Gauss-Hermite integration
rule is used to approximate the required integrals, whereas for 
"ch-Laplace" a fully exponential Laplace approximation method is 
applied. The last option is more suitable for high-dimensional random 
effects vectors, when e.g., modelling nonlinear subject-specific 
trajectories with splines or high-order polynomials.

Sample analyses can be found at:
http://student.kuleuven.be/~m0390867/R%20packages%20&%20Computing/R%20Packages/pbc.R,
and
http://student.kuleuven.be/~m0390867/R%20packages%20&%20Computing/R%20Packages/aids.R

Any kind of feedback (questions, suggestions, bug-reports, etc.) is 
more than welcome.

Best,
Dimitris

----
Dimitris Rizopoulos
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
     http://www.student.kuleuven.be/~m0390867/dimitris.htm



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