Published on in Vol 8, No 7 (2020): July
                                    Preprints (earlier versions) of this paper are
                                    available at
                                    https://preprints.jmir.org/preprint/17653, first published
                                    .
                                

1 Institute of Medical Information & Library, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
2 PingAn Health Technology, Shenzhen, China
*these authors contributed equally
