1. Department of Medicine, National University Hospital , Singapore 119228 , Singapore
2. Yong Loo Lin School of Medicine, National University of Singapore , Singapore 117597 , Singapore
3. Healthy Ageing Programme, Alexandra Hospital , Singapore 159964 , Singapore
4. Department of Haematology-Oncology, National University Cancer Institute of Singapore , Singapore 119228 , Singapore
5. Division of Infectious Diseases , Department of Medicine, , Singapore 119228 , Singapore
6. National University Hospital , Department of Medicine, , Singapore 119228 , Singapore
7. Khoo Teck Puat-National University Children's Medical Institute, National University Hospital , Singapore 119074 , Singapore
8. Fast and Chronic Programmes, Alexandra Hospital , Singapore 159964 , Singapore
9. Division of Advanced Internal Medicine , Department of Medicine, , Singapore 119228 , Singapore