1. Division of Clinical Immunology and Rheumatology, The University of Alabama at Birmingham, Birmingham, Alabama (J.R.C., S.K.)
2. Department of Biostatistics, The University of Alabama at Birmingham, Birmingham, Alabama (S.S.C., J.B.)
3. Hospital for Special Surgery and Weill Cornell Medicine, New York, New York (S.L.B.)
4. Oregon Health & Science University, Portland, Oregon (A.D., S.A.S., K.L.W.)
5. North Georgia Rheumatology Group, Lawrenceville, Georgia (T.L.F.)
6. Arthritis Associates, Hixson, Tennessee (J.H.)
7. University of California, Irvine, Irvine, California (A.J., I.M., N.M.)
8. Altoona Center for Clinical Research, Duncansville, Pennsylvania (A.K.)
9. Ochsner Clinic Foundation, Baton Rouge, Louisiana (S.L.)
10. University of Nebraska Medical Center, Omaha, Nebraska, and FORWARD—The National Databank for Rheumatic Diseases, Wichita, Kansas (K.M.)
11. University of Nebraska Medical Center and VA Nebraska-Western Iowa Health Care System, Omaha, Nebraska (T.R.M.)
12. St. Paul Rheumatology, P.A., Eagan, Minnesota (D.R.)
13. RANA - Rheumatology Associates of North Alabama, Huntsville, Alabama (W.S.).