[1] Univ Sydney, Sydney Local Hlth Dist, Surg Outcomes Res Ctr SOuRCe, Sydney, NSW 2006, Australia
[2] Univ Sydney, Sydney Sch Publ Hlth, Sydney, NSW 2006, Australia
[3] Royal Prince Alfred Hosp, Dept Colorectal Surg, Sydney, NSW 2050, Australia
[4] Sydney Local Hlth Dist, Inst Acad Surg RPA, Sydney, NSW, Australia
[5] Univ Sydney, Sydney, NSW 2006, Australia
[6] Royal Prince Alfred Hosp, Dept Vasc Surg, Sydney, NSW 2050, Australia