Anemia is a common complication in patients with chronic kidney disease (CKD). In addition to erythropoietin deficiency, many studies have identified iron deficiency as a cause of anemia in CKD patients. Most patients with CKD are iron deficient because of: inadequate intake and absorption, gastroenteric bleeding, urinary iron loss in patient with significant proteinuria. The iron treatment is pivotal to manage anemic patients with CKD: the prescription of iron is usually oral because of practicality and safety, but often it is inevitable to administer intravenous iron because of gastroenteric malabsorption, intolerance to oral administration, irregular intake. There're few randomized controlled studies about the efficacy of oral iron versus intravenous iron in patients not on dialysis; most of them demonstrate superiority of intravenous therapy to restore iron deficiency and hemoglobin levels. A particular formulation of iron, liposomal iron has a high gastroenteric absorption and high bioavailability with lower incidence of side effects. The investigators study aims to evaluate the efficacy of treatment with liposomal oral iron compared to intravenous iron in CKD anemic patients not on dialysis in the presence of iron deficiency.

Inclusion Criteria:

• Age ≥ 18 years;
• Signed written informed consent;
• Glomerular filtration rate (GFR) ≤ 60 mL/min (MDRD GFR calculated according to 4 variables);
• hemoglobin ≤ 12g/dL;
• Ferritin ≤ 100ng/mL with transferrin saturation (TSAT) ≤ 25%;
• If erythropoiesis stimulating agents (ESA) therapy, stable dose for at least three months;

Exclusion Criteria:

• Infectious diseases;
• bleeding in the preceding six months;
• History of malignancy tumor in the last 3 years;
• Anemia case different from that resulting from CKD;
• vitamin B12 and folate deficiency;
• Surgery of any kind in the last three months;
• systemic haematological disease;
• Blood Transfusions, therapy with intravenous or oral iron in the last three months;
• Severe liver disease / test positive for hepatitis C virus (HCV) and hepatitis B virus (HBV);
• Abuse of alcohol and drugs in the preceding six months;
• immunosuppressive therapy ;
• Significant weight loss;
• Pregnancy or breast-feeding.