Factors associated with erythropoiesis-stimulating agent hyporesponsiveness anemia in chronic kidney disease patients

Anemia is one of the most common problems in chronic kidney disease (CKD). Despite comprehensive investigations in several cases, definite causes of anemia frequently remain unknown. Our study aimed to analyze the factors that possibly affect anemia in CKD patients who were referred for hematology consultation. A total of 87 patients were retrospectively included in the cohort. Forty-four cases were excluded, including 30 cases with unavailable intact parathyroid hormone (iPTH) data, 11 cases with bone marrow diseases (8 Pure red cell aplasia, 3 Myelodysplastic syndrome) and 3 cases with thalassemia. In total, 43 patients were analyzed. Patients with high iPTH had a significantly lower Hemoglobin (Hb) level and required a higher dose of erythropoiesis stimulating agents (ESAs) compared with the normal iPTH group (Hb 8.29 vs 9.24 mg/dL, P=0.032 and ESAs dose of 16,352.94 vs. 12,444.44 U/week, P=0.024). Univariate, followed by stepwise multivariate analysis was performed and determined that serum phosphate (PO4) was significantly associated with lower Hb level (P=0.01 and P=0.013, respectively). In addition, Hb level was inversely correlated with iPTH and serum phosphate (PO4) level (r=-0.54, P<0.001 and r=-0.47, P=0.005; respectively). Mineral disequilibrium is an important factor associated with anemia in ESA hyporesponsive CKD. Also, hyperphosphatemia and secondary hyperparathyroidism are significantly correlated with low Hb. As a result, we strongly suggest correction of mineral disequilibrium factors prior to performing bone marrow study.