Variational Inference for Gaussian Process Models for Survival Analysis

Gaussian process survival analysis model (GP-SAM) was recently proposed to address key deficiencies of the Cox proportional hazard model, namely the need to account for uncertainty in the hazard function modeling while, at the same time, relaxing the time-covariates factorized assumption of the Cox model. However, the existing MCMC inference algorithms for GPSAM have proven to be slow in practice. In this paper we propose novel and scalable variational inference algorithms for GPSAM that reduce the time complexity of the sampling approaches and improve scalability to large datasets. We accomplish this by employing two effective strategies in scalable GP: i) using pseudo inputs and ii) approximation via random feature expansions. In both setups, we derive the full and partial likelihood formulations, typically considered in survival analysis settings. The proposed approaches are evaluated on two clinical and a divorce-marriage benchmark datasets, where we demonstrate improvements in prediction accuracy over the existing survival analysis methods, while reducing the complexity of inference compared to the recent state-of-the-art MCMC-based algorithms.