[1] Univ Heidelberg Hosp, Dept Clin Social Med Occupat & Environm Dermatol, D-69115 Heidelberg, Germany
[2] German Clin Diagnost, Clin Nephrol, D-65191 Wiesbaden, Germany
[3] Fresenius Med Care, D-61352 Bad Homburg, Germany
[4] Univ Hosp Duesseldorf, Dept Nephrol, D-40001 Dusseldorf, Germany