1. Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea
2. Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
3. Department of Biostatistics, Graduate School of Public Health, Yonsei University, Seoul, Korea
4. Department of Biostatics and Computing, Yonsei University, Seoul, Korea
5. Department of Biostatistics, Yonsei University Wonju College of Medicine, Wonju, Korea
6. Department of Biostatistics, Kyung Hee University Hospital at Gangdong, Korea
7. Department of Internal Medicine, Seoul National University School of Medicine, Seoul, Korea
8. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea