[1] Natl Univ Singapore Hosp, Dept Med, Div Geriatr Med, Singapore, Singapore
[2] Natl Univ Singapore, Yong Loo Lin Sch Med, Dept Microbiol & Immunol, Singapore, Singapore
[3] Natl Univ Singapore, NUS Grad Sch, Integrat Sci & Engn Programme, Singapore, Singapore
[4] Hainan Med Univ, Affiliated Hosp 2, Hainan Clin Res Ctr Acute & Crit Dis, Dept Emergency, Haikou, Peoples R China
[5] Natl Univ Singapore, Yong Loo Lin Sch Med, Hlth Longev Translat Res Programme, Singapore, Singapore
[6] Singapore Inst Clin Sci, Agcy Sci Technol & Res ASTAR, Singapore, Singapore