Magnesium and Muscle Cramps in End Stage Renal Disease Patients on Chronic Hemodialysis

Abstract

We evaluated the frequency and severity of muscle cramps, and the effect of dialysate magnesium on muscle cramps in 62 stable ESRD patients on chronic hemodialysis. Each subject was surveyed twice within a 6-month period. A single nephrology fellow conducted all in-person surveys. During the first survey, the patients were dialyzed with dialysate magnesium of 0.75 meq/L (0.375 mmol/L). Prior to the second survey, the dialysate magnesium was increased to 1.0 meq/L (0.50 mmol/L). The severity of cramps was scored on a 1–10 scale, with 10 indicating maximal severity. The number of patients with muscle cramps was significantly lower with dialysate magnesium of 1.0 meq/L (0.50 mmol/L) (56% versus 77%,P=0.02). No significant difference was observed in interdialytic weight gain, intradialytic ultrafiltration, dry weight, or intradialytic hypotension. The mean ± SD severity score of muscle cramps decreased from5.34±3.61to3.89±3.94(P=0.003). Seven of 31 (23%) patients in the group with low dialysate magnesium while 0/20 (0%) patients receiving high magnesium dialysate terminated hemodialysis early due to cramps (P=0.02). Both the number of patients reporting muscle cramps and the severity score decreased with higher dialysate magnesium which contributed to better adherence to hemodialysis treatments.

A Higher Concentration of Dialysate Magnesium to Reduce the Frequency of Muscle Cramps: A Narrative Review

“…Increasing the concentration of dialysate magnesium by 0.25 mmol/L to 0.50 mmol/L generally causes an increase in patients’ serum magnesium concentration in the subsequent weeks and months. 18 , 22 , 62 - 64 In a recent trial, 59 patients were randomly allocated to dialyze with a dialysate magnesium concentration of 0.5 vs 1.0 mmol/L for 4 weeks; in the group receiving 1.0 mmol/L, patients’ mean serum magnesium levels rose from 0.99 to 1.40 mmol/L. 22 Similar trends have been reported in other prospective studies.…”

“…In the extracellular fluid, 65% of magnesium is ionized, 20% is bound to plasma proteins (eg, albumin and globulin), and 15% is bound to molecules such as phosphate (PO 4 ). 3 - 33…”

“… 13 , 76 A low serum magnesium concentration is linked to more cramps in patients receiving hemodialysis as well as in athletes, older adults, and pregnant women. 5 , 18 , 77 , 78 At least 4 physiologic mechanisms may explain how hypomagnesemia contributes to the development of muscle cramps.…”

“…An example of a nonvalidated but comprehensive cramp assessment in patients receiving hemodialysis is the 10-question assessment designed by Lynch et al (provided in Supplemental Appendix IV ). 18 None of the identified studies used any validated measurement tools.…”

“…We found 6 interventional studies that examined the effect of different dialysate magnesium concentrations or magnesium-based phosphate binders on patient outcomes. 4 , 5 , 18 , 64 , 65 , 99 Only 1 of these studies was specifically designed to assess effects on muscle cramps. 18 In this pre-post study of 62 patients receiving maintenance hemodialysis, patients were surveyed twice about muscle cramps during a 6-month period.…”