Institution: | 1.Department of Internal Medicine,Pusan National University School of Medicine,Yangsan,South Korea;2.Research Institute for Convergence of Biomedical Science and Technology,Pusan National University Yangsan Hospital,Yangsan,South Korea;3.Medical Research Institute,Pusan National University Hospital,Busan,South Korea;4.Division of Nephrology, Department of Internal Medicine,Pusan National University Yangsan Hospital,Yangsan,South Korea |
Abstract: | PurposeErythropoietin (EPO) deficiency and resistance to endogenous EPO is an important pathophysiological feature in anemia of chronic kidney disease (CKD). Low 1,25 dihydroxyvitamin D 1,25(OH)2D] level is known to contribute to anemia of CKD. We aimed to investigate the associations between serum 1,25(OH)2D and anemia, EPO deficiency, and endogenous EPO resistance in patients with CKD.MethodsThis study included 409 patients with CKD glomerular filtration rate (GFR)?<?60 ml/min/1.73 m2] who were not on dialysis therapy. Patients on exogenous EPO therapy and patients with iron deficiencies were excluded. Endogenous EPO resistance was assessed by calculating the ratio of endogenous EPO to hemoglobin (Hb) (endogenous EPO/Hb ratio). The associations of Hb level, endogenous EPO level, and the endogenous EPO/Hb ratio with clinical and laboratory variables were investigated by univariate and multivariate analyses.ResultsIn univariate analysis, serum 1,25(OH)2D level was correlated with the Hb level, endogenous EPO level, and the endogenous EPO/Hb ratio. Multiple regression analysis revealed that the serum 1,25(OH)2D level remained significantly associated with the Hb level (β?=?0.532, P?<?0.001), endogenous EPO level (β?=?0.149, P?=?0.010), and the endogenous EPO/Hb ratio (β?=???0.187, P?=?0.002), even after adjusting for other confounding factors, including the levels of parathyroid hormone and the inflammatory marker C-reactive protein.ConclusionThe serum 1,25(OH)2D level exhibited significant associations with anemia, EPO deficiency, and endogenous EPO resistance in CKD patients. These associations were independent of secondary hyperparathyroidism and inflammation status. |