 Patients randomised to the FERINJECT group will receive between 500 mg and 2000 mg of FERINJECT, according to their Hb and body weight, in up to 3 infusions. The maximum infused weekly dose of will be 1000 mg. For patients in the VENOFER group, the individual iron deficit will be calculated per individual using the modified formula of Ganzoni. Patients will receive one infusion of 200 mg of VENOFER twice a week, up to 11 infusions, depending on their calculated iron deficit. Due to the relatively large doses of iron being administered, patients will be monitored carefully throughout the study for symptoms of iron overload. 