Department of Mathematics, Hong Kong University of Science and Technology, Hong Kong, China.|Shenzhen Research Institute of Big Data, Shenzhen, China.|Centre for Quantitative Medicine, Program in Health Services and Systems Research, Duke-NUS Medical School, Singapore.|Department of Medicine, University of Chicago, Chicago, IL, USA.|Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA.|Centre for Quantitative Medicine, Program in Health Services and Systems Research, Duke-NUS Medical School, Singapore.