[1] Tan Tock Seng Hosp, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore
[2] Natl Univ Singapore, Yong Loo Lin Sch Med, Alice Lee Ctr Nursing Studies, Clin Res Ctr, Block MD11,Level 2,10 Med Dr, Singapore 117597, Singapore
[3] Edith Cowan Univ, Ctr Res Aged Care, Sch Nursing & Midwifery, 270 Joondalup Dr, Joondalup, WA 6027, Australia
[4] Natl Univ Singapore, Yong Loo Lin Sch Med, Alice Lee Ctr Nursing Studies, Clin Res Ctr, Block MD11,Level 2,10 Med Dr, Singapore 117597, Singapore