1. Rheumatology Division, Department of Medicine, the Feinberg School of Medicine, Northwestern University, Chicago, Illinois.
2. Departments of Preventive Medicine and Physical Medicine and Rehabilitation, the Feinberg School of Medicine, Northwestern University, Chicago, Illinois.
3. Arthritis Center, Rehabilitation Institute of Chicago, Chicago, Illinois.
4. Institute of Healthcare Studies, the Feinberg School of Medicine, Northwestern University, Chicago, Illinois.