1. Department of Nephrology; Ajou University School of Medicine; Suwon Korea
2. Department of Pulmonary and Critical Care Medicine; Ajou University School of Medicine; Suwon Korea
3. Department of Biomedical Informatics; Ajou University School of Medicine; Suwon Korea
4. College of Pharmacy; Ajou University; Suwon Korea
5. Center for Clinical Epidemiology; and Biostatistics, and Department of Biostatistics & Epidemiology; Perelman School of Medicine at the University of Pennsylvania; Philadelphia PA USA
6. Center for Pharmacoepidemiololgy Research and Training; Perelman School of Medicine at the University of Pennsylvania; Philadelphia PA USA