[1] Tan Tock Seng Hosp, Dept Gen Surg, Singapore, Singapore
[2] Woodlands Hlth, Dept Surg, 2 Yishun Cent 2, Singapore 76802, Singapore
[3] ASTAR, Skin Res Inst Singapore, Singapore, Singapore
[4] Singapore Gen Hosp, Dept Vasc Surg, Singapore, Singapore
[5] Singapore Gen Hosp, Dept Endocrinol, Singapore, Singapore
[6] Singapore Gen Hosp, Nursing Div, Singapore, Singapore
[7] Natl Univ Singapore Hosp, Dept Cardiac Thorac & Vasc Surg, Singapore, Singapore
[8] Duke NUS Med Sch, Hlth Serv & Syst Res, Singapore, Singapore