1. From the Departments of Medicine (D.C.C., E.R.M.) and Epidemiology (E.R.M.), Johns Hopkins University, Baltimore, Md; Department of Medicine (L.C.P., N.R.P.), San Francisco General Hospital and University of California, San Francisco, Calif; Department of Medicine (R.S., E.H.) and Kidney Epidemiology and Cost Center (R.S., E.H.), University of Michigan, Ann Arbor, Mich; Centers for Disease Control and Prevention (S.H.S., D.E.W.), Atlanta, Ga.