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The effect of magnesium supplementation on vascular calcification in chronic kidney disease—a randomised clinical trial (MAGiCAL-CKD): essential study design and rationale
  1. Iain Bressendorff1,
  2. Ditte Hansen2,
  3. Morten Schou3,
  4. Charlotte Kragelund3,
  5. Lisbet Brandi1
  1. 1 Department of Cardiology, Nephrology, and Endocrinology, Nordsjællands Hospital, Hillerød, Denmark
  2. 2 Department of Nephrology, Herlev and Gentofte Hospital, Herlev, Denmark
  3. 3 Department of Cardiology, Herlev and Gentofte Hospital, Herlev, Denmark
  1. Correspondence to Dr Iain Bressendorff; iain{at}


Introduction Chronic kidney disease (CKD) is associated with an increased risk of cardiovascular disease and mortality, which is thought to be caused by increased propensity towards vascular calcification (VC). Magnesium (Mg) inhibits phosphate-induced VC in vitro and in animal models and serum Mg is inversely associated with cardiovascular mortality in predialysis CKD and in end-stage renal disease. This paper will describe the design and rationale of a randomised double-blinded placebo-controlled multicentre clinical trial, which will investigate whether oral Mg supplementation can prevent the progression of coronary artery calcification (CAC) in subjects with predialysis CKD.

Methods and analysis We will randomise 250 subjects with estimated glomerular filtration rate of 15 to 45 mL/min/1.73 m2 to 12 months treatment with either slow-release Mg hydroxide 30 mmol/day or matching placebo in a 1:1 ratio. The primary end point is change in CAC score as measured by CT at baseline and after 12 months treatment. Secondary end points include change in pulse wave velocity, bone mineral density, measures of mineral metabolism and clinical end points related to cardiovascular and renal events.

Ethics and dissemination This trial has been approved by the local biomedical research ethics committees and data protection agencies and will be performed in accordance with the latest revision of the Helsinki Declaration. The trial will examine for the first time the effect of increasing the uptake of a putative VC inhibitor (ie, Mg) on progression of CAC in subjects with predialysis CKD.

Trial registration number NCT02542319, pre-results.

  • Magnesium
  • vascular calcification
  • chronic kidney disease
  • mineral metabolism
  • randomised clinical trial

This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:

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  • Contributors IB, DH, MS, CK and LB conceived the trial. IB wrote the initial draft. DH, MS, CK and LB provided feedback and comments. All authors approved the final version of the manuscript prior to submission. IB took responsibility for the submission process.

  • Funding This work is funded by Nordsjælland’s Hospital’s Research Foundation, The Danish Society of Nephrology’s Research Foundation, Helen and Ejnar Bjørnow’s Foundation, The Danish Kidney Foundation and The Toyota Foundation. Gunnar Kjems provided the study medication free of charge but has had no role in the design of the trial.

  • Competing interests None declared.

  • Ethics approval The Danish National Committees on Biomedical Research Ethics and the Norwegian National Committees on Biomedical Research Ethics.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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