1. Richard A. and Susan F. Smith Center for Outcomes Research, Cardiovascular Division, Beth Israel Deaconess Medical Center, Boston, MA (R.K.W.).
2. Harvard Medical School, Boston, MA (R.K.W.).
3. Cardiovascular Division, John T. Milliken Department of Internal Medicine and Center for Advancing Health Services, Policy & Economics Research, Washington University School of Medicine in St. Louis, MO (K.E.J.M.).