[1] Northwestern Univ, Inst Hlth Serv Res & Policy Studies, Feinberg Sch Med, Chicago, IL 60611 USA
[2] Northwestern Univ, Dept Rheumatol, Chicago, IL 60611 USA
[3] Northwestern Univ, Div Rheumatol, Dept Med, Dept Prevent Med,Dept Phys Med & Rehabil, Chicago, IL 60611 USA
[4] Rehabil Inst Chicago, Dept Phys Med & Rehabil, Chicago, IL 60611 USA
[5] Rehabil Inst Chicago, Ctr Arthritis, Chicago, IL 60611 USA
[6] Northwestern Univ, Multidisciplinary Clin Res Ctr Rheumatol, Chicago, IL 60611 USA