[1] Univ Wisconsin, Sch Med & Publ Hlth, Dept Surg, Wisconsin Surg Outcomes Res Program, Madison, WI USA
[2] Univ Wisconsin, Carbone Canc Ctr, Sch Med & Publ Hlth, Madison, WI USA
[3] Washington Univ, Dept Surg, St Louis, MO USA
[4] Denver Hlth & Hosp Author, Denver Publ Hlth, Denver, CO USA
[5] Univ Pittsburgh, Dept Surg, Pittsburgh, PA USA