You will be provided with a reference and some statements. Please determine whether each statement is 'supported', 'unsupported', or 'unknown' with respect to the reference. Please note:
First, assess whether the reference contains any valid content. If the reference contains no valid information, such as a 'page not found' message, then all statements should be considered 'unknown'.
If the reference is valid, for a given statement: if the facts or data it contains can be found entirely or partially within the reference, it is considered 'supported' (data accepts rounding); if all facts and data in the statement cannot be found in the reference, it is considered 'unsupported'.

You should return the result in a JSON list format, where each item in the list contains the statement's index and the judgment result, for example:
[
    {
        "idx": 1,
        "result": "supported"
    },
    {
        "idx": 2,
        "result": "unsupported"
    }
]

Below are the reference and statements:
<reference>
The Effect of Magnesium Supplementation on... : Journal of the American Society of Nephrology



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Clinical Research
:
Chronic Kidney Disease
The Effect of Magnesium Supplementation on Vascular Calcification in CKD: A Randomized Clinical Trial (MAGiCAL-CKD)
Iain

Bressendorff
2
Ditte

Hansen
2
Morten

Schou
3
Charlotte

Kragelund
4
My

Svensson
5
Bahram

Hashemi
6
Tilde

Kristensen
7
Marie Houmaa

Vrist
8
Rikke

Borg
9
Birgitte

Tougaard
10
Kristine

Borg
11
Henrik Øder

Hjortkjær
12
Cathrine Helgestad

Kristiansen
13
Nicholas

Carlson
14
Mohammad

Nasiri
15
Haseem

Ashraf
16
Andreas

Pasch
18
Lisbet

Brandi
1
Authors and Affiliations
Journal of the American Society of Nephrology

34
(
5
)
:p
886
-
894
,
May 2023
.
|
DOI:
10.1681/ASN.0000000000000092
Infographic
Abstract
Significance Statement
Magnesium prevents vascular calcification in animals with CKD. In addition, lower serum magnesium is associated with higher risk of cardiovascular events in CKD. In a randomized, double-blinded, placebo-controlled trial, the authors investigated the effects of magnesium supplementation versus placebo on vascular calcification in patients with predialysis CKD. Despite significant increases in plasma magnesium among study participants who received magnesium compared with those who received placebo, magnesium supplementation did not slow the progression of vascular calcification in study participants. In addition, the findings showed a higher incidence of serious adverse events in the group treated with magnesium. Magnesium supplementation alone was not sufficient to delay progression of vascular calcification, and other therapeutic strategies might be necessary to reduce the risk of cardiovascular disease in CKD.
Background
Elevated levels of serum magnesium are associated with lower risk of cardiovascular events in patients with CKD. Magnesium also prevents vascular calcification in animal models of CKD.
Methods
To investigate whether oral magnesium supplementation would slow the progression of vascular calcification in CKD, we conducted a randomized, double-blinded, placebo-controlled, parallel-group, clinical trial. We enrolled 148 subjects with an eGFR between 15 and 45 ml/min and randomly assigned them to receive oral magnesium hydroxide 15 mmol twice daily or matching placebo for 12 months. The primary end point was the between-groups difference in coronary artery calcification (CAC) score after 12 months adjusted for baseline CAC score, age, and diabetes mellitus.
Results
A total of 75 subjects received magnesium and 73 received placebo. Median eGFR was 25 ml/min at baseline, and median baseline CAC scores were 413 and 274 in the magnesium and placebo groups, respectively. Despite plasma magnesium increasing significantly during the trial in the magnesium group, the baseline-adjusted CAC scores did not differ significantly between the two groups after 12 months. Prespecified subgroup analyses according to CAC>0 at baseline, diabetes mellitus, or tertiles of serum calcification propensity did not significantly alter the main results. Among subjects who experienced gastrointestinal adverse effects, 35 were in the group receiving magnesium treatment versus nine in the placebo group. Five deaths and six cardiovascular events occurred in the magnesium group compared with two deaths and no cardiovascular events in the placebo group.
Conclusions
Magnesium supplementation for 12 months did not slow the progression of vascular calcification in CKD, despite a significant increase in plasma magnesium.
Clinical Trials Registration
www.clinicaltrials.gov
(
NCT02542319
).
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Copyright © 2023 by the American Society of Nephrology
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</reference>

<statements>
1. Given that low serum magnesium is associated with higher cardiovascular event risk in chronic kidney disease (CKD), and that magnesium inhibits phosphate-induced vascular calcification in experimental models, a randomized trial (MAGiCAL-CKD) was conducted in predialysis CKD patients.
2. In this trial, 148 subjects with estimated GFR 15–45 mL/min were randomized to oral magnesium hydroxide (15 mmol twice daily) or placebo for 12 months. Despite significant increases in plasma magnesium in the intervention group, magnesium supplementation did not slow the progression of coronary artery calcification (CAC) compared with placebo. Moreover, serious adverse events, including deaths and major cardiovascular events, were more frequent in the magnesium group, and gastrointestinal side effects were common.
3. These results suggest that simply raising plasma magnesium in CKD is not sufficient to halt vascular calcification and may introduce safety concerns, particularly at relatively high doses and in patients with limited renal function.
4. Magnesium, zinc, and selenium supplements are widely available, inexpensive, and have been used in many trials, demonstrating practical feasibility for chronic administration. Adherence is generally good, although gastrointestinal side effects (especially with magnesium) can limit tolerability.
5. Magnesium supplementation is generally safe in individuals with normal renal function, but high-dose regimens in CKD patients have been linked to increased serious adverse events and gastrointestinal intolerance. Hypermagnesemia is a concern in advanced renal failure.
</statements>

Begin the assessment now. Output only the JSON list, without any conversational text or explanations.