[1] Tan Tock Seng Hosp, Dept Geriatr Med, Singapore 308433, Singapore
[2] Tan Tock Seng Hosp, Clin Res Unit, Singapore 308433, Singapore
[3] St Lukes Hosp, Singapore, Singapore
[4] Alexandra Hosp, Dept Geriatr Med, Singapore, Singapore
[5] Natl Univ Singapore Hosp, Dept Med, Singapore 119074, Singapore
[6] Renci Hosp & Med Ctr, Singapore, Singapore
[7] Ang Mo Kio Thye Hua Kwan Hosp, Singapore, Singapore