Visit 2 (start of study, month 0): The patient's current medication will be recorded (with particular reference to the following concomitant medication: ACE inhibitors, AngII blockers, statins, erythropoietin, beta-blockers). Questions will be asked about newly developed diseases with special attention to the occurrence of diabetes mellitus, coronary heart disease, stroke (including transitory ischaemic attacks [TIA] and prolonged reversible ischaemic neurological deficit [PRIND]) and peripheral arterial occlusive disease. The blood pressure, pulse rate and body mass index will be recorded. Study medication for 28 weeks will be issued. The patient will be informed about taking the medicament. Laboratory values will be recorded in the course of the routine monitoring of the patients (abbreviated and extensive routine laboratory examinations: hemoglobin, leukocyte count, platelet count, calcium, calcium x phosphate product, urea, serum creatinine, total protein, parathyroid hormone, cholesterol, triglycerides and ferritin). The patient will be asked about current symptoms.