Kidney Week

Abstract: SA-PO746

Routine Hemodialysis Does Not Result in Optimal Plasma Magnesium Concentrations

Session Information

• Standard Hemodialysis for ESRD - I
  November 04, 2017 | Location: Hall H, Morial Convention Center
  Abstract Time: 10:00 AM - 10:00 AM

Category: Dialysis

• 601 Standard Hemodialysis for ESRD

Authors

• Leenders, Niki H.j., VU University Medical Center, Amsterdam, Netherlands

Niki H.j. Leenders,

• Hoekstra, Tiny, VU University Medical Center, Amsterdam, Netherlands

Tiny Hoekstra,

• van Ittersum, Frans J., VU University Medical Center, Amsterdam, Netherlands

Frans J. van Ittersum,

• Hoenderop, Joost, Radboud university medical center, Nijmegen, Netherlands

Joost Hoenderop,

• Vervloet, Marc G., VU University Medical Center, Amsterdam, Netherlands

Marc G. Vervloet,

Background

Lower plasma magnesium (Mg) concentrations have been associated with a higher overall and cardiovascular mortality in hemodialysis patients. The optimal level of plasma Mg in hemodialysis patients appears to be above the reference range for the healthy population (typically 0.70-1.00 mmol/L). Plasma Mg is not routinely measured after hemodialysis. Aim of this study was to determine the effect of standard hemodialysis treatment on plasma Mg.

Methods

Plasma Mg was measured in duplicate before (Mg_pre) and after (Mg_post) 6 consecutive dialysis sessions in 34 patients on a regular 3 times weekly hemodialysis schedule with a standard 0.50 mmol/L dialysate magnesium concentration.

Results

Mean Mg_pre was 0.88 mmol/L (SD 0.14), 76% of patients had a mean Mg_pre below 1.00 and the coefficient of intra-individual biological variation was 5.6%. Post-dialysis, mean Mg was decreased to 0.78 (SD 0.06, p<0.001).
Univariate linear regression showed that mean Mg_pre and Mg_post in an individual were positively correlated (p<0.001) and the regression line indicated that Mg was stable during dialysis at a Mg_pre of 0.73, decreased at a Mg_pre above 0.73 and increased at a Mg_pre below 0.73.
In an analysis with linear mixed models a 0.10 mmol/L higher Mg_pre was associated with a 0.03 mmol/L higher Mg_post (95%-CI 0.024-0.037, p<0.001). If added to the model, baseline factors including gender, age, serum albumin, height and weight; and dialysis characteristics including vascular access type, dialysis duration, ultrafiltration volume, blood flow and dialysis efficiency did not change this association.

Conclusion

In the majority of the hemodialysis patients Mg_pre is suboptimal. Routine hemodialysis further declines magnesium in the majority of patients. Current dialysate magnesium concentrations may be too low.

Funding

• Private Foundation Support