SP546CONVERSION FROM LOW TO HIGH MAGNESIUM DIALYSATE: A SINGLE CENTER EXPERIENCE

Abstract

Introduction and Aims: Magnesium (Mg) is the fourth most abundant cation in the human body and has direct effects on many physiological variables, e.g. blood pressure, myocardial contractility, bone mineralization and parathyroid function in patients with normal kidney function. Its role in patients with chronic kidney disease is less clearly understood but recent studies have linked hypomagnesemia to an increased cardiovascular risk. Methods: In patients on hemodialysis serum Mg levels are importantly influenced by the dialysis fluid Mg concentration. We changed our center's standard Mg dialysis fluid concentration from 0.5 mmol/L to 1.0 mmol/L under the hypothesis that this would have beneficial effects on intradialytic hemodynamic stability. In 45 chronic hemodialysis patients, we retrospectively compared event rates of instable intradialytic blood pressure requiring volume resuscitation during one year before and after the change in dialysis fluid Mg concentration. In addition we assessed biochemical markers of bone and lipid metabolism, as well as parameters of the hematopoietic system. Results: Increasing dialysis fluid Mg to 1.0 mmol/L was well tolerated by all patients and was associated with a general trend towards higher intradialytic hemodynamic stability. Event rates decreased significantly in patients with recurrent events in the year prior to Mg change. Contrary to previously published data, there were no significant changes in phosphate and iPTH levels but we found a significant drop in serum calcium and 25‐OH‐vitamin D levels. Additionally, total cholesterol as well as LDL cholesterol levels increased significantly after changing to 1.0 mmol/L of Mg, while HDL cholesterol and triglycerides did not change. Interestingly, we recognized a significant reduction in hemoglobin, paralleled by highly significant drop of erythrocyte indices such as MCV, MCH, and MCHC. Conclusions: Increasing dialysis fluid Mg from 0.5 mmol/L to 1.0 mmol/L improved hemodynamic stability during hemodialysis sessions. In parallel, we observed unexpected effects on bone and lipid metabolism, and on red blood cell physiology. These data which underline the complex interplay of serum Mg with several biological systems need further exploration and should be investigated in a prospective fashion in hemodialysis patients.