1. Department of Internal Medicine, Hospital Lahad Datu, Peti Bersurat 60065, Lahad Datu, Sabah 91110, Malaysia
2. Department of Internal Medicine, Hospital Sultanah Nora Ismail, Jalan Korma, Batu Pahat, Johor, Taman Soga 83000, Malaysia. email: cheosengwee@gmail.com