Efficient Gibbs Sampling in Cox Regression Models Using Composite Partial Likelihood and Pólya-Gamma Augmentation

Abstract: The Cox regression model and its Bayesian extensions are widely used in survival analysis. However, standard Bayesian approaches require modeling of the baseline hazard, and their full conditional distributions lack closed-form expressions. Therefore, the Metropolis-Hastings sampling algorithm is typically employed, whose efficiency is highly sensitive to the choice of proposal distribution. To address these issues, we propose the GS4Cox, an efficient Gibbs sampling algorithm for the Cox regression model based on four key components: (i) general Bayesian framework, (ii) composite partial likelihood, (iii) P\'olya-Gamma augmentation scheme, and (iv) finite corrections. Our experiments on both synthetic and actual datasets demonstrate that the GS4Cox algorithm outperforms existing sampling methods in terms of convergence speed and sampling efficiency.