1 Internal Medicine Residency, National University Health System, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
2 Saw Swee Hock School of Public Health, National University of Singapore, Singapore.
3 Saw Swee Hock School of Public Health, National University of Singapore, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
4 Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Cardiology, National University Heart Centre, Singapore.
5 Department of Respiratory Medicine, Ng Teng Fong General Hospital, Jurong Health Services, 1 Jurong East Street 21, 609606, Singapore. Electronic address: ayytan@gmail.com.