“70-year-old male with a hx of CKD stage 4 (GFR 25 and Cr. 2.2) comes in c/o of fatigue. Hgb is low at 9; Serum iron low at 30 (N 60 -170); TIBC and Ferritin are normal. MCV is 77.
Kidney function has been like that for over a year. Recent colonoscopy was normal and FOBT is negative.
Which one of the following would be most appropriate at this point?
A) An erythropoietin level
B) Transfusion of packed RBCs
C) Epoetin alfa (Procrit)
D) Ferrous sulfate orally
E) Intravenous iron therapy
ANSWER: D
Chronic kidney disease (CKD) is now divided into five stages of progressively worsening function based on the glomerular filtration rate (GFR). Stage 1 is defined as a GFR >90 mL/min/1.73 m2, while the fifth stage, kidney failure, is defined as a GFR <15 mL/min/1.73 m2. Anemia is associated with not only stage 5 disease, where it is universal, but also with earlier stages. The National Kidney Foundation Guidelines
define anemia as a hemoglobin level £13.5 g/dL in men or £12.0 g/dL in women.
Anemia due to CKD is diagnosed by excluding other etiologies. Anemia in CKD is due to decreased production of erythropoietin, but testing for levels is not needed, nor is a bone marrow biopsy. The indicated tests include a CBC, reticulocyte count, ferritin level, vitamin B12 level, folate level, and transferrin saturation (serum iron to total iron binding capacity ratio). Usually the CBC will demonstrate a normochromic, normocytic anemia, but can show microcytosis (mean corpuscular volume <80). A serum ferritin level <25 ng/mL is indicative of low iron stores. Some patients have a combination of iron
deficiency and anemia of chronic disease due to the kidney disease.
Patients with depleted iron stores will benefit from replenishment, which serves to correct an isolated iron deficiency or improve the response to erythropoiesis-stimulating agents. Iron therapy is generally initiated orally with ferrous sulfate, 325 mg 3 times a day. The effectiveness of this therapy can be monitored by checking hemoglobin, transferrin saturation, and ferritin levels at 1 and 3 months after beginning treatment. If the goals have not been achieved by 3 months, intravenous iron therapy should be considered.
For patients who do not respond to iron replacement, erythropoiesis-stimulating agents such as epoetin alfa or darbepoetin alfa should be used. The goal should be to relieve symptoms such as fatigue and to achieve a hemoglobin level of 11–12 g/dL. Levels >13 g/dL increase the mortality rate, particularly from cardiovascular disease.” ABFM question
References
Anemia in older persons. Am Fam Physician 2010;82(5):480-487.
Update on the management of chronic kidney disease. Am Fam Physician 2012;86(8):749-754.
FP Essentials monograph series, no 416, 2014, pp 22-25.”