[1] Univ Calif San Francisco, Div Nephrol, Dept Med, San Francisco, CA 94143 USA
[2] Fletcher Allen Hlth Care, Thrombosis & Hemostasis Program, Hematol Oncol Clin, Burlington, VT 05401 USA
[3] Div Epidemiol & Community Hlth, Minneapolis, MN 55454 USA
[4] 7E121 VA Pittsburgh Healthcare Syst, Div Nephrol, Univ Dr Ctr, Pittsburgh, PA 15240 USA
[5] Columbia Univ, Presbyterian Hosp, Dept Internal Med, New York, NY 10032 USA
[6] UCSD Sch Med, Dept Family & Prevent Med, La Jolla, CA 92093 USA
[7] San Francisco VA Med Ctr, Div Gen Internal Med, San Francisco, CA 94143 USA