[1] Childrens Mem Hosp, Chicago, IL 60614 USA
[2] Northwestern Univ, Feinberg Sch Med, Inst Healthcare Studies, Chicago, IL 60611 USA
[3] Northwestern Univ, Feinberg Sch Med, Div Gen Internal Med, Chicago, IL 60611 USA
[4] Amer Acad Family Physicians, Robert Graham Ctr Policy Studies Family Med & Pri, Washington, DC USA
[5] Univ Illinois, Dept Med, Sect Hlth Promot, Chicago, IL USA
[6] Cook Cty Hosp, Dept Med, Div Pulm & Crit Care Med, Chicago, IL 60612 USA
[7] US Dept Vet Affairs, Vet Affairs Edward Hines Jr Hosp, Ctr Management Complex Chron Care, Hines, IL 60141 USA