作者单位:Vanderbilt Univ, Med Ctr, Div Nephrol, Nashville, TN 37232 USA[1]Stanford Univ, Div Nephrol, Palo Alto, CA 94304 USA[2]San Francisco Dept Vet Affairs Med Ctr, Dept Med, San Francisco, CA USA[3]Baylor Coll Med, Dept Med, Div Nephrol, Houston, TX 77030 USA[4]