1. From the Cardiovascular Special Studies Center (C.A.H., J.Z.M., A.J.C.), United States Renal Data System, Minneapolis, Minn; the Department of Preventive Medicine (J.Z.M.), University of Tennessee, Memphis; and the Department of Internal Medicine, Divisions of Cardiology (C.A.H.) and Nephrology (A.J.C.), Hennepin County Medical Center, University of Minnesota, Minneapolis.