Switch From Oral Iron to Intravenous Ferric Carboxymaltose in Non-dialysis Chronic Kidney Disease (CKD)

Inclusion Criteria: * \>18 years of age * Creatinine clearance ≤40 mL/min * Hemoglobin 110-120 g/L * Serum ferritin \<100 µg/L or transferrin saturation \<20% * Monthly treatment with ESA and oral iron for at least six months before enrolment Exclusion Criteria: * Other obvious cause of acute or chronic anemia than iron deficiency * Expectation to require hemodialysis within the next six months * Short life expectancy (\<1 year) * Pregnancy * Decompensated heart failure * History of allergic reactions to iron preparations and/or anaphylaxis from any cause * Requirement of blood transfusions * Chronic decompensated mental disorder or dementia