1. Birmingham and Tuscaloosa Health Services Research and Development Unit, Birmingham Veterans Affairs Medical Center, Birmingham, Alabama2Department of Surgery, University of Alabama at Birmingham
2. Department of Surgery, Veterans Affairs Palo Alto Healthcare System, Palo Alto, California4Department of Surgery, Stanford University, Stanford, California
3. Veterans Affairs Central Western Massachusetts Health Care System, Leeds6Center for Applied Health Research, Baylor Scott & White Health, Temple, Texas7Department of Medicine, Texas A&M Health Science Center, Temple
4. Department of Surgery, Milwaukee Veterans Affairs Medical Center, Milwaukee, Wisconsin9Department of Medicine, Medical College of Wisconsin, Milwaukee
5. Department of Surgery, Veterans Affairs Boston Healthcare System, Boston, Massachusetts11Department of Surgery, Boston University School of Medicine, Boston, Massachusetts12School of Medicine, Harvard University, Boston, Massachusetts