1. Hannover Medical School, Department of Nephrology and Hypertension, Hannover, Germany
2. KRH Klinikum Siloah, Department of Respiratory and Critical Care Medicine, Hanover, Germany
3. Academic Teaching Hospital Braunschweig, Medical Clinic V Nephrology | Rheumatology | Blood Purification, Braunschweig
4. Klinikum Aschaffenburg-Alzenau, Medizinische Klinik I, Alzenau
5. St. Joseph Krankenhaus Berlin-Tempelhof, Med. Abteilung II, Berlin
6. University Hospital Erlangen, Medical Clinic 4 – Nephrology and Hypertension, Erlangen