[1] Vanderbilt Univ, Med Ctr, Dept Biomed Informat, 2525 West End Ave, Nashville, TN 37212 USA
[2] Tennessee Valley Healthcare Syst VA, Geriatr Res Educ & Clin Care Serv, Nashville, TN USA
[3] Math Policy Res, Washington, DC USA
[4] Stanford Univ, Sch Med, Stanford, CA 94305 USA