摘要：Cluster failure time data are commonly encountered in survival analysis due to different
factors such as shared environmental conditions and genetic similarity. In such
cases, careful attention needs to be paid to the correlation among subjects within same
clusters. In this paper, we study a frailty model based on Birnbaum–Saunders frailty
distribution. We approximate the intractable integrals in the likelihood function by
the use of Monte Carlo simulations and then use the piecewise constant baseline hazard
function within the proportional hazards model in frailty framework. Thereafter,
the maximum likelihood estimates are numerically determined. A simulation study is
conducted to evaluate the performance of the proposed model and the method of inference.
Finally, we apply this model to a real data set to analyze the effect of sublingual
nitroglycerin and oral isosorbide dinitrate on angina pectoris of coronary heart disease
patients and compare our results with those based on other frailty models considered
earlier in the literature.
关键词：Birnbaum;Saunders distribution; censored data; cluster time data; frailty model;
Monte Carlo simulation; piecewise constant hazards;
