[1] Univ Calif San Diego, Dept Med, Div Nephrol & Hypertens, Vet Affairs San Diego Healthcare Syst, San Diego, CA 92161 USA
[2] Univ Calif San Diego, Div Nephrol & Hypertens, Vet Affairs Healthcare Syst, San Diego, CA 92103 USA
[3] Univ Calif San Diego, Dept Med, Vet Affairs Heathcare Syst, San Diego, CA USA
[4] Vet Affairs San Diego Healthcare Syst, Dept Med, San Diego, CA USA
[5] Tufts Univ New England Med Ctr, Dept Med, Div Nephrol, Boston, MA 02111 USA
[6] Cleveland Clin Fdn, Dept Quantitat Hlth Sci, Cleveland, OH 44195 USA
[7] Univ Utah, Dept Med, Div Clin Epidemiol, Salt Lake City, UT 84112 USA
[8] NIH, Bethesda, MD 20892 USA
[9] Hennepin Cty Med Ctr, Dept Med, Div Nephrol, Minneapolis, MN 55415 USA