This study examines patients with chronic kidney disease-related anemia and measures changes in the metabolism of the heart using FDG/PET scanning, before and 6 months after their health-care provider has initiated anemia management therapy with the FDA-approved drug darbepoetin alfa (Aranesp), which is approved for chronic kidney disease-related anemia. The investigators hypothesize that the heart has abnormal metabolism with the anemia of chronic kidney disease but this improves after correction of this anemia with darbepoetin alfa.

Inclusion Criteria:

• Participant must receive care at the VAMHCS (VA Hospital) in Baltimore
• Diagnosed with CKD stage 3 to 5 (eGFR of 60 ml/min/1.73m2) and not expected to initiate renal replacement therapy within 6 months
• Anemia related CKD.
• The last 2 serum hemoglobin (Hb) values less than 11.0 gm/dl but greater than 8.0 gm/dl
• Greater than 18 years of age
• Assessed to be clinically stable by the clinician

Exclusion Criteria:

• Need for hemodialysis, peritoneal dialysis, or transplantation at the time of enrollment or projected to start within 6 months after enrollment
• Low functional capacity including inability to walk a flight of stairs with a bag of groceries (NYHA Class III/IV Heart Failure)
• Prior erythropoietic agents within last 12 weeks
• TSAT < 15% and not receiving the recommended dose for iron deficiency
• Uncontrolled hypertension defined as greater than 180 mm Hg systolic or 110 mm Hg diastolic
• Potentially "brittle" diabetes with the propensity for symptomatic hypoglycemia after a 6 hour fast
• New diagnosis or ongoing therapy for Cancer
• Pregnancy

The study population consists of individuals being followed for their chronic kidney disease (CKD) at one of the Nephrology/Early Renal Insufficiency Clinics at the Baltimore, Maryland VA Medical Center and are being considered for erthropoietin therapy for anemia related to CKD.