Magnesium Administration in Chronic Kidney Disease.

Awareness of the clinical relevance of magnesium in medicine has increased over the last years, especially for people with chronic kidney disease (CKD), due to magnesium's role in vascular calcification and mineral metabolism. The inverse association between serum magnesium and clinically relevant, adverse outcomes is well-established in people with CKD. Subsequent intervention studies have focused on the effect of magnesium administration, mainly in relation to cardiovascular diseases, mineral bone metabolism, and other metabolic parameters. The most commonly used routes of magnesium administration are orally and by increasing dialysate magnesium. Several oral magnesium formulations are available and the daily dosage of elemental magnesium varies highly between studies, causing considerable heterogeneity. Although data are still limited, several clinical studies demonstrated that magnesium administration could improve parameters of vascular function and calcification and mineral metabolism in people with CKD. Current clinical research has shown that magnesium administration in people with CKD is safe, without concerns for severe hypermagnesemia or negative interference with bone metabolism. It should be noted that there are several ongoing magnesium intervention studies that will contribute to the increasing knowledge on the potential of magnesium administration in people with CKD.

Reversal Of Arterial Disease by modulating Magnesium and Phosphate (ROADMAP-study): rationale and design of a randomized controlled trial assessing the effects of magnesium citrate supplementation and phosphate-binding therapy on arterial stiffness in moderate chronic kidney disease.

BACKGROUND: Arterial stiffness and calcification propensity are associated with high cardiovascular risk and increased mortality in chronic kidney disease (CKD). Both magnesium and phosphate are recognized as modulators of vascular calcification and chronic inflammation, both features of CKD that contribute to arterial stiffness. In this paper, we outline the rationale and design of a randomized controlled trial (RCT) investigating whether 24 weeks of oral magnesium supplementation with or without additional phosphate-binding therapy can improve arterial stiffness and calcification propensity in patients with stage 3-4 CKD. METHODS: In this multi-center, placebo-controlled RCT, a total of 180 participants with an estimated glomerular filtration rate of 15 to 50 ml/min/1.73 m2 without phosphate binder therapy will be recruited. During the 24 weeks intervention, participants will be randomized to one of four intervention groups to receive either magnesium citrate (350 mg elemental magnesium/day) or placebo, with or without the addition of the phosphate binder sucroferric oxyhydroxide (1000 mg/day). Primary outcome of the study is the change of arterial stiffness measured by the carotid-femoral pulse wave velocity over 24 weeks. Secondary outcomes include markers of calcification and inflammation, among others calcification propensity (T50) and high-sensitivity C-reactive protein. As explorative endpoints, repeated 18F-FDG and 18F-NaF PET-scans will be performed in a subset of participants (n = 40). Measurements of primary and secondary endpoints are performed at baseline, 12 and 24 weeks. DISCUSSION: The combined intervention of magnesium citrate supplementation and phosphate-lowering therapy with sucroferric oxyhydroxide, in stage 3-4 CKD patients without overt hyperphosphatemia, aims to modulate the complex and deregulated mineral metabolism leading to vascular calcification and arterial stiffness and to establish to what extent this is mediated by T50 changes. The results of this combined intervention may contribute to future early interventions for CKD patients to reduce the risk of CVD and mortality. TRIAL REGISTRATION: Netherlands Trial Register, NL8252 (registered December 2019), EU clinical Trial Register 2019-001306-23 (registered November 2019).

Magnesium intake and vascular structure and function: the Hoorn Study.

PURPOSE: Circulating and dietary magnesium have been shown to be inversely associated with the prevalence of cardiovascular disease (CVD) and mortality in both high and low-risk populations. We aimed to examine the association between dietary magnesium intake and several measures of vascular structure and function in a prospective cohort. METHODS: We included 789 participants who participated in the vascular screening sub-cohort of the Hoorn Study, a population-based, prospective cohort study. Baseline dietary magnesium intake was estimated with a validated food frequency questionnaire and categorised in energy-adjusted magnesium intake tertiles. Several measurements of vascular structure and function were performed at baseline and most measurements were repeated after 8 years of follow-up (n = 432). Multivariable linear and logistic regression was performed to study the cross-sectional and longitudinal associations of magnesium intake and intima-media thickness (IMT), augmentation index (Aix), pulse wave velocity (PWV), flow-mediated dilatation (FMD), and peripheral arterial disease (PAD). RESULTS: Mean absolute magnesium intake was 328 ± 83 mg/day and prior CVD and DM2 was present in 55 and 41% of the participants, respectively. Multivariable regression analyses did not demonstrate associations between magnesium intake and any of the vascular outcomes. Participants in the highest compared to the lowest magnesium intake tertile demonstrated in fully adjusted cross-sectional analyses a PWV of -0.21 m/s (95% confidence interval -1.95, 1.52), a FMD of -0.03% (-0.89, 0.83) and in longitudinal analyses an IMT of 0.01 mm (-0.03, 0.06), an Aix of 0.70% (-1.69, 3.07) and an odds ratio of 0.84 (0.23, 3.11) for PAD CONCLUSION: We did not find associations between dietary magnesium intake and multiple markers of vascular structure and function, in either cross-sectional or longitudinal analyses.

Serum Magnesium Is Inversely Associated With Heart Failure, Atrial Fibrillation, and Microvascular Complications in Type 2 Diabetes.

OBJECTIVE: We investigated whether serum magnesium (Mg2+) was prospectively associated with macro- or microvascular complications and mediated by glycemic control (hemoglobin A1c [HbA1c]), in type 2 diabetes (T2D). RESEARCH DESIGN AND METHODS: We analyzed in 4,348 participants the association of serum Mg2+ with macrovascular disease and mortality (acute myocardial infarction [AMI], coronary heart disease [CHD], heart failure [HF], cerebrovascular accident [CVA], and peripheral arterial disease [PAD]), atrial fibrillation (AF), and microvascular complications (chronic kidney disease [CKD], diabetic retinopathy, and diabetic foot) using Cox regression, adjusted for confounders. Mediation analysis was performed to assess whether HbA1c mediated these associations. RESULTS: The average baseline serum Mg2+ concentration was 0.80 ± 0.08 mmol/L. During 6.1 years of follow-up, serum Mg2+ was inversely associated with major macrovascular, 0.87 (95% CI 0.76; 1.00); HF, 0.76 (95% CI 0.62; 0.93); and AF, 0.59 (95% CI 0.49; 0.72). Serum Mg2+ was not associated with AMI, CHD, CVA, and PAD. During 5.1 years of follow-up, serum Mg2+ was inversely associated with overall microvascular events, 0.85 (95% CI 0.78; 0.91); 0.89 (95% CI 0.82; 0.96) for CKD, 0.77 (95% CI 0.61; 0.98) for diabetic retinopathy, and 0.85 (95% CI 0.78; 0.92) for diabetic foot. HbA1c mediated the associations of serum Mg2+ with HF, overall microvascular events, diabetic retinopathy, and diabetic foot. CONCLUSIONS: Serum Mg2+ concentration is inversely associated with the risk to develop HF and AF and with the occurrence of CKD, diabetic retinopathy, and foot complications in T2D. Glycemic control partially mediated the association of serum Mg2+ with HF and microvascular complications.

The association between circulating magnesium and clinically relevant outcomes in patients with chronic kidney disease: A systematic review and meta-analysis.

BACKGROUND & AIMS: Despite modern treatment, risk for cardiovascular disease and mortality in patients with chronic kidney disease (CKD) is unacceptably high. Observational studies have shown associations of magnesium with risk for several clinical outcomes in CKD of variable magnitude. The aim of this review is to provide a systematic overview and meta-analysis of longitudinal studies assessing the association of plasma magnesium concentration with clinically relevant outcomes in adult patients with chronic kidney disease, with a minimal follow-up of 6 months. Primary outcomes of interest were all-cause mortality, cardiovascular mortality, cardiovascular events, sudden death and hospitalisation. METHODS: The electronic databases PubMed, Embase and The Cochrane Library were searched using terms relating to plasma magnesium and CKD patients, and two authors independently selected eligible studies. Study quality was assessed according to the Newcastle-Ottawa Scale. Results of studies with a comparable magnesium exposure and outcome measure, were pooled using a random-effects meta-regression analysis. RESULTS: The search yielded 6156 records of which 33 studies, involving 348,059 patients, met the eligibility criteria. Finally, 22 studies could be included in the meta-analysis. Higher magnesium was associated with a lower risk for all-cause mortality (HR 0.90 [0.87-0.94] per 0.1 mmol/L increase of magnesium) and cardiovascular mortality and events (HR 0.85 [0.77-0.94] per 0.1 mmol/L). CONCLUSIONS: Magnesium concentration is inversely associated with all-cause mortality and cardiovascular mortality and events. Therefore, increasing magnesium may improve risk in patients with chronic kidney disease. This meta-analysis forms a firm base for future prospective trials to test whether increasing plasma magnesium, indeed has beneficial effects on clinical outcomes.

Serum Calcification Propensity and the Risk of Cardiovascular and All-Cause Mortality in the General Population: The PREVEND Study.

OBJECTIVE: Vascular calcification contributes to the cause of cardiovascular disease. The calciprotein particle maturation time (T50) in serum, a measure of calcification propensity, has been linked with adverse outcomes in patients with chronic kidney disease, but its role in the general population is unclear. We investigated whether serum T50 is associated with cardiovascular mortality in a large general population-based cohort. Approach and Results: The relationship between serum T50 and cardiovascular mortality was studied in 6231 participants of the PREVEND (Prevention of Renal and Vascular End-Stage Disease) cohort. All-cause mortality was the secondary outcome. Mean (±SD) age was 53±12 years, 50% were male, and mean serum T50 was 329±58 minutes. A shorter serum T50 is indicative of a higher calcification propensity. Serum T50 was inversely associated with circulating phosphate, age, estimated glomerular filtration rate, and alcohol consumption, whereas plasma magnesium was positively associated with serum T50 (P<0.001, total multivariable model R2=0.281). During median (interquartile range) follow-up for 8.3 (7.8-8.9) years, 364 patients died (5.8%), of whom 95 (26.1%) died from a cardiovascular cause. In multivariable Cox proportional hazard models, each 60 minutes decrease in serum T50 was independently associated with a higher risk of cardiovascular mortality (fully adjusted hazard ratio [95% CI], 1.22 [1.04-1.36], P=0.021). This association was modified by diabetes mellitus; stratified analysis indicated a more pronounced association in individuals with diabetes mellitus. CONCLUSIONS: Serum T50 is independently associated with an increased risk of cardiovascular mortality in the general population and thus may be an early and potentially modifiable risk marker for cardiovascular mortality.