1. Wisconsin Surgical Outcomes Research Program, Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
2. William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
3. Wolff Center at University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
4. Department of Surgery, University of Nebraska Medical Center, Omaha, Nebraska
5. Nebraska–Western Iowa Veterans Affairs (VA) Health System, Omaha, Nebraska
6. Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
7. Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
8. Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
9. Center for Health Equity Research and Promotion, VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania
10. Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania