Joint Modeling of Death Times and Counts Using a Random Effects Model

  • Published : 2005.11.30

Abstract

We consider the problem of modeling count data where the observation period is determined by the survival time of the individual under study. We assume random effects or frailty model to allow for a possible association between the death times and the counts. We assume that, given a random effect, the death times follow a Weibull distribution with a rate that depends on some covariates. For the counts, given the random effect, a Poisson process is assumed with the intensity depending on time and the covariates. A gamma model is assumed for the random effect. Maximum likelihood estimators of the model parameters are obtained. The model is applied to data set of patients with breast cancer who received a bone marrow transplant. A model for the time to death and the number of supportive transfusions a patient received is constructed and consequences of the model are examined.

Keywords

References

  1. Journal of Clinical Oncology v.15 High-Dose Chemotherapy with Autologous Hematopoietic Stem-Cell Support for Breast Cancer in North America Antman, K.H.(et al.)
  2. Biometrika v.5 A Model for Association in Bivariate Life Tables and Its Application in Epidemiological Studies of Familial Tendency in Chronic Disease Incidence Clayton, D.G.
  3. Biometrics v.48 Semiparametric Estimation of Random Effects Using The Cox Model Based on the EM Algorithm Klein, J.P.
  4. Survival Analysis: Techniques for Censored and Truncated Data Klein, J.P.;Moeschberger, M.L.
  5. Estimating Random Effects in The Framingham Heart Study;Survival Analysis: State of The Art Klein, J.P.;Moeschberger, M.L.;Li, Y.H.;Wang, S.T.;Klein, J.P.(ed.);Goel, P.(ed.)
  6. JASA v.82 Regression Methods for Poisson Process Data Lawless, J.F.
  7. SIME Journal of Applied Mathematics v.11 An Algorithm for Least-Squares Estimation of Non-Linear Parameters Marquardt, D.
  8. Journal of Statistics v.19 A Counting Process Approach to Maximum Likelihood Estimation in Frailty Models Nielsen, G.G.;Gill, R.D.;Andersen, P.K.;Sorensen, T.I.A.