Association between Serum Magnesium and Erythropoietin Responsiveness in Hemodialysis Patients: A Cross-Sectional Study.

Background/aims: As shown in the China Health and Nutrition Survey, serum magnesium is associated with anemia. However, the roles of magnesium in anemia and erythropoietin (EPO) responsiveness remain unclear in maintenance hemodialysis (MHD) patients. This study aims to investigate the level of serum magnesium and its relationship with EPO responsiveness in MHD patients.

Methods: A total of 307 MHD patients were recruited for this survey. Laboratory data and anthropometrics were collected. EPO responsiveness was evaluated by the erythropoietin resistance index (ERI). The subjects were divided into 3 groups according to serum magnesium concentrations (group A, the lowest tertile; group B, the middle tertiles; and group C, the highest tertile). Multivariate logistic regressions were conducted to evaluate the factors that may be associated with EPO responsiveness.

Results: The mean serum magnesium level was significantly higher than normal levels in MHD patients, while no hypomagnesemia was observed. A multivariate logistic regression model revealed that high-sensitivity C-reactive protein, intact parathyroid hormone, serum albumin, and magnesium levels were correlated with a high ERI. The OR of a high ERI was found to be 2.57 (95% CI 1.330-4.975, p = 0.005) for group A and 1.66 (95% CI 0.878--3.140, p > 0.05) for group B compared with the OR for group C.

Conclusion: Serum magnesium levels were higher than normal levels in MHD patients. A high serum magnesium level was correlated with good EPO responsiveness and was therefore suggested to be a protective factor for EPO hyporesponsiveness.