1. and the Departments of Medicine and Community and Family Medicine, Dartmouth Medical School (A.N.A.T.), Hanover, NH; the Department of Medicine (L.G.), University of California San Francisco, School of Medicine; and the Section for Clinical Epidemiology, the Division for General Medicine and the Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School (T.H.L.), and the Department of Health Care Policy, Harvard Medical School (S.U.), Boston, Mass.