1 Department of General Medicine, Tan Tock Seng Hospital, Singapore.
2 National Public Health and Epidemiology Unit, National Centre for Infectious Diseases, we, Singapore.
3 Department of Rehabilitation Medicine, Tan Tock Seng Hospital, Singapore.
4 Department of Endocrinology, Tan Tock Seng Hospital; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore; Department of Medicine, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.