[1] Univ Colorado, Sch Med, Div Gen Internal Med, Dept Med, Mail Stop B180,12631 E 17th Ave, Aurora, CO 80045 USA
[2] Johns Hopkins Sch Med, Div Gen Internal Med, Baltimore, MD USA
[3] Johns Hopkins Univ, Sch Med, Div Infect Dis, Baltimore, MD USA
[4] Univ Washington, Sch Med, Div Gen Internal Med, Seattle, WA USA
[5] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Epidemiol, Baltimore, MD USA