1. Division of Geriatric Medicine , Department of Internal Medicine , Faculty of Medicine , Khon Kaen University , Khon Kaen 40002 , Thailand
2. Department of Emergency Medicine , Faculty of Medicine , Khon Kaen University , Khon Kaen 40002 , Thailand
3. Department of Internal Medicine , Faculty of Medicine , Khon Kaen University , Khon Kaen 40002 , Thailand