1. From the Division of Research, Kaiser Permanente of Northern California, Oakland (A.S.G., N.U., N.K.P.); Departments of Epidemiology, Biostatistics, and Medicine, University of California at San Francisco (A.S.G., M.C.F.); and Clinical Epidemiology Unit, General Medicine Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston (Y.C., L.B., D.E.S.).