1 Department of Internal Medicine, College of Medicine, Seoul National University, Seoul, Korea; Department of Internal Medicine, Inje University Ilsan Paik Hospital, Ilsan, Korea.
2 Department of Kidney Research Institute, Seoul National University, Seoul, Korea.
3 Department of Internal Medicine, College of Medicine, Seoul National University, Seoul, Korea; Department of Kidney Research Institute, Seoul National University, Seoul, Korea; Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea. Electronic address: dkkim73@gmail.com.