1. Department of Internal Medicine, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea.
2. Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu, Korea.
3. Department of Internal Medicine, Chonbuk National University Hospital, Chonnam National University Medical School, Jeonju, Korea.
4. Department of Internal Medicine, Yeungnam University Medical Center, Yeungnam University College of Medicine, Daegu, Korea.
5. Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea.