1 Division of Nephrology, Bone and Mineral Metabolism, University of Kentucky, Lexington, Kentucky, USA. Electronic address: amr.elhusseini.moh@uky.edu.
2 Nephrology and Dialysis Unit, Mansoura University, Mansoura, Egypt.
3 Division of Nephrology, Federal University of Paraná, Curitiba, Paraná, Brazil.