Magnesium in chronic hemodialysis

Patients treated with hemodialysis (HD) are at increased risk for all-cause and cardiovascular (CV) mortality even after adjustments for traditional CV risk factors. The authors identified lower plasma magnesium (pMg) as a risk factor for arrhythmias and sudden death in people treated with HD. The aim of this study was to determine the connection between dialysate Mg concentrations (dMg) and the clinical characteristics of patients on chronic HD.

An observational study including 103 chronic HD patients. Patients were divided into two groups based on dMg: group 1 (dMg = 0.5 mmol/L) and group 2 (dMg = 1 mmol/L). Variables were collected from patients' medical documentation.

There was no statistically significant difference between the groups regarding mean age (58.7 ± 14.6 vs. 58.9 ± 14.3 years, p = 0.972), HD duration (4 ± 0.3 vs. 4 ± 0.5 h, p = 0.849), mean Qb (283.3 ± 22.8 vs. 285.7 ± 21.9 mL/min, p = 0.597), mean Kt/V (1.53 ± 0.38 vs. 1.62 ± 0.35, p = 0.262) and mean dCa (1.61 ± 0.19 vs. 1.61 ± 0.16 mmol/L, p = 0.793). We found pMg concentration to be statistically significantly lower and intact parathyroid hormone (iPTH), to be statistically significantly higher in the low dMg group: 0.97 ± 0.73 vs. 1.31 ± 0.25 mmol/L, p = 0.007 and 242 (127 - 487) vs. 108 (47 - 290.75), p < 0.001, respectively. Mean QT interval did not differ significantly between the groups (380.7 ± 46.3 vs. 387.7 ± 50.3 ms, p = 0.488).

Higher dMg significantly increased pMg concentrations without significantly impacting the QT interval. This way we could safely increase pMg concentrations while potentially providing benefits regarding the control of secondary hyperparathyroidism.