Published on in Vol 7, No 1 (2019): Jan-Mar
                                    Preprints (earlier versions) of this paper are
                                    available at
                                    https://preprints.jmir.org/preprint/11487, first published
                                    .
                                

1 University of Texas Southwestern Medical Center, Dallas, TX, United States
2 University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
