Weibull Extension of Bivariate Exponential Regression Model with Gamma Frailty for Survival Data

Abstract A maximum likelihood estimation procedure is developed for a bivariate frailty regression model, in which dependence is generated by a gamma distribution. It is assumed that the random lifetimes follow a bivariate Weibull distribution proposed in Hanagal [Economic Quality Control 11: 193-200, 1996] and that censoring is independent of the two lifetimes. The proposed model may be applied for survival times in genetic epidemiology, survival times of dental implants of patients and survival times of twin births (both monozygotic and dizygotic), with genetic frailty behavior (which is unknown and random) of patients.