DENVER – African-Americans (AAs) appear to have more severe vitamin D deficiency and elevations of parathyroid hormone (PTH) across all stages of CKD compared with other races, according to researchers at the University of Chicago.
Jennifer L. Ennis, MD, and colleagues concluded that AA race is a novel and unexplained risk factor for elevated PTH in CKD patients independent of other established factors.
A prior study showed higher rates of vitamin D deficiency and increased serum calcium (Ca), phosphorus (P), and PTH levels in AAs compared with non-AAs with pre-dialysis CKD (Kidney Int. 2008;73:956-962). However, few studies have focused on these issues in all CKD patients. Researchers performed a cross-sectional analysis of laboratory data collected on 817 AA and 2,162 non-AA patients with stage 1-5 CKD enrolled in the Litholink CKD program. Serum Ca, P, 25-hydroxyvitamin D (25 Vit D) and plasma PTH levels were compared between the two groups.
The researchers found that mean plasma PTH values were higher and mean 25 vitamin D values were lower in AAs compared with non-AAs across all CKD stages. In addition, differences reached statistical significance for PTH in stages 2-5 and for 25 Vit D in stages 1-3. However, unlike the previous published study, mean Ca and P did not differ between the two groups at any stage.
The researchers noted that this is the largest analysis of mineral metabolism in AA CKD patients. They noted that AAs now comprise a significant and growing portion of the CKD population.