Universitätsmedizin Mannheim, Vth Department of Medicine, Medical Faculty of the University of Heidelberg, Mannheim, Germany. Division of Nephrology and Dialysis, Ospedale Maggiore di Milano IRCCS, Milano, Italy. Landeskrankenhaus, University of Innsbruck, Innsbruck, Austria. Katharinenhospital, Stuttgart, Germany. Hospital Ramón y Cajal, Madrid, Spain. Universitätsklinik des Saarlandes, Homburg, Germany. Klinik für Nephrologie, University of Kiel, Kiel, Germany. Universitätsklinik Münster, Münster, Germany. Universitá di Padova, Padua, Italy. Universitá di Vicenza, Vicenza, Italy. Koehler eClinical GmbH, Freiburg, Germany. Abteilung für Nephrologie, University of Regensburg, Regensburg, Germany. Allgemeines Krankenhaus Wien, Medical University of Vienna, Austria. Hospital Marqués de Valdecilla, Santander, Spain.