  The wide implementation of electronic health record (EHR) systems facilitates
the collection of large-scale health data from real clinical settings. Despite
the significant increase in adoption of EHR systems, this data remains largely
unexplored, but presents a rich data source for knowledge discovery from
patient health histories in tasks such as understanding disease correlations
and predicting health outcomes. However, the heterogeneity, sparsity, noise,
and bias in this data present many complex challenges. This complexity makes it
difficult to translate potentially relevant information into machine learning
algorithms. In this paper, we propose a computational framework, Patient2Vec,
to learn an interpretable deep representation of longitudinal EHR data which is
personalized for each patient. To evaluate this approach, we apply it to the
prediction of future hospitalizations using real EHR data and compare its
predictive performance with baseline methods. Patient2Vec produces a vector
space with meaningful structure and it achieves an AUC around 0.799
outperforming baseline methods. In the end, the learned feature importance can
be visualized and interpreted at both the individual and population levels to
bring clinical insights.
