1. Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Solna, Sweden
2. Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
3. Department of Medical Informatics, ERA-EDTA Registry, Amsterdam University Medical Center, Amsterdam Public Health Research Institute, University of Amsterdam, Amsterdam, The Netherlands
4. CNR-IFC, Clinical Epidemiology of Renal Diseases and Hypertension, Reggio Calabria, Italy