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Abstract: TH-PO136

Effect of Citrate-Buffered, Magnesium-Enriched Dialysate on Calcification Propensity in Hemodialysis Patients: Results of a Randomized Controlled Trial (CitMag Study)

Session Information

Category: Bone and Mineral Metabolism

  • 502 Bone and Mineral Metabolism: Clinical


  • Cejka, Daniel, Ordensklinikum Linz GmbH, Linz, Oberösterreich, Austria
  • Thiem, Ursula, Ordensklinikum Linz GmbH, Linz, Oberösterreich, Austria
  • Blinzler, Eric, Ordensklinikum Linz GmbH, Linz, Oberösterreich, Austria
  • Machacek, Jennifer Daniela, Ordensklinikum Linz GmbH, Linz, Oberösterreich, Austria
  • Voelkl, Jakob, Johannes Kepler Universitat Linz, Linz, Austria
  • Smith, Edward R., The Royal Melbourne Hospital, Parkville, Victoria, Australia
  • Pasch, Andreas, Calciscon AG, Biel, Switzerland
  • Haller, Maria C., Ordensklinikum Linz GmbH, Linz, Oberösterreich, Austria

Accelerated serum calcification propensity (lower T50 time) is directly associated with increased risk of cardiovascular events and mortality in dialysis patients. Several solitary interventions have been reported to improve T50 but whether a combination of these interventions yields further increases T50 is unknown. Therefore, the effect of substituting acetate for citrate buffer in combination with increases in magnesium concentration in dialysate on T50 was investigated.


In a randomized, controlled trial, 60 chronic hemodialysis patients were allocated to either continue on standard (S) dialysate (3 mmol/l acetate, 0.5 mmol/l magnesium) or a sequence of magnesium-enriched (Mg0.75) dialysate (3 mmol/l acetate, 0.75 mmol/l magnesium) for 2 weeks followed by citrate-buffered, magnesium-enriched (Cit+Mg0.75) dialysate (1 mmol/l citrate, 0.75 mmol/l magnesium) for 3 weeks. The primary endpoint was the difference in T50 times between the S group and the Cit+Mg0.75 group at 5 weeks.


There was no significant difference in T50 time between the S group compared to the Cit+Mg0.75 group (236 ± 77 vs. 265 ± 97 minutes, p=0.23). The size of secondary calciprotein particles (CPP-2Rh) did not differ between the S group and the Cit+Mg0.75 group (294 ± 95 vs. 309 ± 91 nm, p=0.55). In longitudinal analyses, serum magnesium concentrations increased from 1.07 ± 0.17 to 1.24 ± 0.17 mmol/l with the Mg0.75 dialysate (p<0.0001) but decreased again to 1.19 ± 0.16 mmol/l with the Cit+Mg0.75 dialysate (p<0.0001). Serum bicarbonate levels did not change significantly throughout the study.


The combination of citrate-buffer with increased magnesium concentration in dialysate does not improve T50 and may even be antagonistic when administered concurrently.


  • Government Support – Non-U.S.