1. School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania
2. Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
3. Physician Network and Quality, St Clair Hospital, Pittsburgh, Pennsylvania
4. Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania
5. Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
6. Intermountain Healthcare Rehabilitation Services, Murray, Utah
7. Johns Hopkins University School of Medicine, Baltimore, Maryland
8. Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
9. Johns Hopkins Hospital, Baltimore, Maryland
10. Department of Physical Therapy, University of Florida College of Public Health and Health Professions, Gainesville
11. Duke Clinical Research Institute, Department of Orthopedic Surgery, Duke University, Durham, North Carolina
12. Department of Family Medicine, Boston Medical Center, Boston, Massachusetts