Relationship between serum magnesium level and coronary artery calcification in maintenance hemodialysis patients

Objective To evaluate the relationship between serum magnesium and coronary artery calcification (CAC) and their associated factors. Methods 131 patients with chronic kidney disease on regular hemodialysis (HD) were recruited into this study from December 2014 to December 2015 in our center. Demographic and clinical data of selected patients were collected. Serum fibroblast growth factor 23 (FGF-23) level was quantified by enzyme linked immunosorbent assay(ELISA). Quantification of coronary artery calcification score (CACs) was determined by multi-slice spiral computed tomography (MSCT). The relationships between serum magnesium and FGF-23 level, CACs, demographic and clinical data were investigated. Results Patients were divided into low serum magnesium group, normal serum magnesium group and high serum magnesium group according to their serum magnesium levels. There were significant differences in the distribution of diabetes history, serum phosphorus, serum albumin, serum pre albumin, serum uric acid among these three groups(P＜0.05). A significant positive correlation was confirmed between serum magnesium level and serum albumin, serum pre albumin, serum phosphorus and serum uric acid by Pearson correlation analysis and Spearman correlation analysis (r=0.389, 0.234, 0.200, 0.234, P=0.000, 0.007, 0.022, 0.007, respectively). According to the degree of CAC, all maintenance hemodialysis (MHD) patients were divided into non-calcification group, low calcification group, moderate calcification group and high calcification group, and there were significant differences in the distribution of the age, serum phosphorus, serum magnesium, FGF-23 levels among these groups (P＜0.05) . Spearman correlation analysis showed that CACs was positively correlated with age, FGF-23, serum phosphorus (r=0.309, 0.277, 0.180, P=0.000, 0.001, 0.040, respectively), while negatively correlated with serum magnesium level (r=-0.238, P=0.006) in patients with MHD. The independent risk factors of CACs were aging, high level of FGF-23 in MHD patients by using ordinal logistic regression. However, Hypermagnesemia was a protective factor. Conclusions The history of diabetes, low serum albumin, phosphorus metabolism disorder and CAC are associated with hypomagnesemia in MHD patients. In MHD patients, aging as well as high level of FGF-23 are the risk factors of CAC, and hypermagnesemia is a protective factor of CAC.