1. Department of Internal Medicine, Ewha Medical Research Institute, Ewha Womans University School of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
3. Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
4. Department of Internal Medicine, Konyang University College of Medicine, Daejeon, Korea.
5. Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea.
6. Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
7. Clinical Trial Center, Ewha Womans University Medical Center, Seoul, Korea.