A living kidney donor recently asked me if there was a connection between kidney donation and anemia. Because I’m not a walking encyclopedia, I put my google-fu to work and learned a lot along the way.
An analysis of NHANES III found that a GFR <60 was associated with a lower hemoglobin level and a higher prevalence of anemia.
(Note:Hemoglobin is the part of the red blood cell that carries iron and helps transport oxygen throughout the body.)
“The prevalence of anemia was 1.8% among those with an estimated GFR of 90 or higher, compared with 5.2% among those with an estimated GFR between 30 and 59, and 44.1% among those with an estimated GFR between 15 and 29.”
“Non-Hispanic black persons had a lower mean hemoglobin level than non-Hispanic white persons. Older age, female sex, and elevated CRP [C-reactive protein] level were also significantly associated with lower hemoglobin levels.”
This article has multiple tables and figures; go check them out.
A study of 5222 folks diagnosed with chronic kidney disease but not yet on dialysis (meaning they have not yet progressed to end-stage renal disease) found a higher prevalence of anemia as GFR declines.
“Percentage of patients with hemoglobin less than or equal to 12 g/dL [the cut-off for an anemia diagnosis] increased from 26.7% to 75.5% when glomerular filtration rate decreased from greater than or equal to 60 to < 15.”
“Prevalence of hemoglobin less than or equal to 10 g/dL increased substantially from 5.2% to 27.2% when glomerular filtration rate diminished from 60 to < 15.”
“Anemia was present in 47.7% of 5222 predialysis patients with chronic kidney disease”
Nurko states that most people “with chronic kidney disease eventually become anemic”.
“Factors likely contributing to anemia in chronic kidney disease include blood loss, shortened red cell life span, vitamin deficiencies, the “uremic milieu,” erythropoietin (EPO) deficiency, iron deficiency, and inflammation.”
“Deficiency of erythropoietin is the primary cause of anemia in chronic renal failure, but it is not the only cause. A minimal workup is necessary to rule out iron deficiency and other cell-line abnormalities.”
Erythropoietin is a protein excreted by the kidneys (yet another thing potential living kidney donors aren’t told prior to donating) which promotes the formation of red blood cells by the bone marrow. The kidney cells responsible for making erythropoietin are sensitive to oxygen levels in the blood, releasing erythropoietin when they drop too low. Red blood cells, as well, carry oxygen.
“Researchers postulate that the specialized peritubular cells that produce EPO are partially or completely depleted or injured as renal disease progresses, so that EPO production is inappropriately low relative to the degree of anemia”
“The consensus is that untreated anemia contributes to the large cardiovascular disease burden in [the CKD} population.”
“Left ventricular hypertrophy is closely linked to chronic kidney disease. The estimated prevalence in stage 3 and 4 is 39%, and it is even higher in patients with lower renal function”
If iron supplements don’t correct the issue, this author recommends the addition of an erythropoiesis-stimulating agent (ESA). “Studies suggest that treating anemia with a goal of raising the hematocrit to at least 36% improves quality of life, decreases the need for transfusions, improves muscle strength and cognitive function, and decreases rates of hospitalization and death”
Take care of yourself!