2Division of Nephrology, Department of Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea
3Nephrology Section, VA Long Beach Healthcare System, Long Beach, CA, USA
4Division of Nephrology, Department of Internal Medicine, Ewha Womans University College of Medicine, Ewha Medical Research Center, Seoul, Korea
5Division of Nephrology, Department of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA
6Nephrology Section, Memphis Veterans Affairs Medical Center, Memphis, TN, USA