1. From the Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark (H.T.S., E.H.-P., T.L.L., C.F.C., L.P.); Department of Cardiothoracic and Vascular Sciences, Thromboembolism Unit, University of Padua, Padua, Italy (R.R., P.P.); Departments of Medicine and Community and Family Medicine, Dartmouth Medical School, Hanover, NH (J.A.B.).