1. Assistant Professor, Division of Respiratory and Respiratory Critical Care Medicine, Department of Medicine, Faculty of Medicine, Prince of Songkla University, Hatyai, Songkhla 90110, Thailand
2. Division of Respiratory and Respiratory Critical Care Medicine, Department of Medicine, Faculty of Medicine, Songklanakarind Hospital, Prince of Songkla University, Songkhla, Thailand
3. Department of Medicine, Bangkok Hospital Hatyai, Songkhla,Thailand