This article is part of our ongoing coverage of Renal Week 2009. Click here for a complete list of our Renal Week Live articles.
Key Points
- Elevated levels of vitamin D are associated with higher hemoglobin levels in CKD patients with diabetes.
- Diabetics with a 25-hydroxyvitamin D (25-OHD) level in the highest quartile had a mean hemoglobin concentration 0.86 g/dL higher than those in the lowest quartile.
- Each doubling of 25-OHD was associated with a 0.33 g/dL increase in hemoglobin.
Elevated levels of vitamin D are associated with higher hemoglobin levels in CKD patients with diabetes, according to researchers at the University of Missouri School of Medicine in Columbia in a study presented at ASN’s Renal Week 2009.
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Diabetics with a 25-hydroxyvitamin D (25-OHD) level in the highest quartile had a mean hemoglobin concentration 0.86 g/dL higher than those in the lowest quartile. After adjusting for age, race, gender, and estimated glomerular filtration rate, each doubling of 25-OHD was associated with a 0.33 g/dL increase in hemoglobin, Diptesh Gupta, MD, and colleagues reported.
Among non-diabetics, hemoglobin concentrations were the same across 25-OHD quartiles.
The study population included 509 CKD patients, of whom 67% were men, 84% were Caucasian, and 48% had diabetes. Patients had a mean age of 64 years.
The authors noted that vitamin D has synergistic properties with erythropoietin (EPO) in the stimulation of hematopoeisis. In CKD, diabetics tend to be anemic at earlier stages than non-diabetics, possibly due to lower EPO.
As to why the association between elevated vitamin D levels and higher hemoglobin was observed only in diabetics, Dr. Gupta, who reported study findings at Renal Week 2009 in San Diego, noted that the diabetics tend to have lower EPO levels than non-diabetics, and data show that vitamin D upregulates EPO receptors. Thus, the positive effect on hemoglobin may be more apparent in diabetics.
He noted that other researchers have postulated about different mechanisms, such as suppression of tumor necrosis factor alfa by vitamin D, leading to a decrease in inflammation and improvement in hemoglobin.
