Magnesium and outcomes in patients with chronic kidney disease: focus on vascular calcification, atherosclerosis and survival

Dietary Calcium to Magnesium Ratio and Risk of Cardiovascular Diseases

Dietary factors are critical risk factors for cardiovascular diseases (CVD). Among various aspects of dietary intake, the dietary calcium-to-magnesium (Ca: Mg) ratio has been less studied. The present study aimed to evaluate the association of the dietary Ca: Mg ratio with 10-year cardiovascular risk among participants of the health cohort of medical staff in Shiraz, Iran. This cross-sectional study utilized baseline data from the Shiraz University of Medical Sciences Employees' Health Cohort Study (SUMS EHCS). Demographic, anthropometric, and laboratory data were collected. A 113-item food frequency questionnaire was used to assess dietary intake. The 10-year risk of developing cardiovascular disease (CVD) was estimated using the Framingham Risk Score. Linear regression modeling examined the association between the dietary Ca: Mg ratio and 10-year coronary risk. Of the SUMS EHCS participants, 3,382 subjects (1,515 males and 1,867 females) with a median (IQR) age of 41.00 (10.00) years were eligible for the study. In both univariate and adjusted models, a 1-unit increase in the Ca: Mg ratio was associated with higher levels of 10-year coronary risk: B = 0.097 (95% CI: 0.044, 0.150) in the univariate model and B = 0.091 (95% CI: 0.038, 0.143) in the adjusted model. The findings indicated that a higher dietary Ca: Mg ratio was associated with a higher 10-year risk of CVD.

Risk factors for cardio-cerebrovascular events among patients undergoing continuous ambulatory peritoneal dialysis and their association with serum magnesium

Serum magnesium levels exceeding 0.9 mmol/L are associated with increased survival rates in patients with CKD. This retrospective study aimed to identify risk factors for cardio-cerebrovascular events among patients receiving continuous ambulatory peritoneal dialysis (CAPD) and to examine their correlations with serum magnesium levels. Sociodemographic data, clinical physiological and biochemical indexes, and cardio-cerebrovascular event data were collected from 189 patients undergoing CAPD. Risk factors associated with cardio-cerebrovascular events were identified by univariate binary logistic regression analysis. Correlations between the risk factors and serum magnesium levels were determined by correlation analysis. Univariate regression analysis identified age, C-reactive protein (CRP), red cell volume distribution width standard deviation, red cell volume distribution width corpuscular volume, serum albumin, serum potassium, serum sodium, serum chlorine, serum magnesium, and serum uric acid as risk factors for cardio-cerebrovascular events. Among them, serum magnesium ≤0.8 mmol/L had the highest odds ratio (3.996). Multivariate regression analysis revealed that serum magnesium was an independent risk factor, while serum UA (<440 μmol/L) was an independent protective factor for cardio-cerebrovascular events. The incidence of cardio-cerebrovascular events differed significantly among patients with different grades of serum magnesium (χ2 = 12.023, p = 0.002), with the highest incidence observed in patients with a serum magnesium concentration <0.8 mmol/L. High serum magnesium levels were correlated with high levels of serum albumin (r = 0.399, p < 0.001), serum potassium (r = 0.423, p < 0.001), and serum uric acid (r = 0.411, p < 0.001), and low levels of CRP (r = -0.279, p < 0.001). In conclusion, low serum magnesium may predict cardio-cerebrovascular events in patients receiving CAPD.

Association of magnesium intake with predicted atherosclerotic lesions and cardiovascular risk in young adults based on PDAY score: a cross-sectional study

BACKGROUND

Magnesium deficiency has been shown to accelerate atherosclerosis. We hypothesized that dietary magnesium intake at a young age is associated with future atherosclerotic lesions and cardiovascular risk in a large, nationally representative cohort of U.S. adults.

METHODS

We included U.S. adults aged 20 to 34 years old from the National Health and Nutrition Examination Survey (NHANES) 2007 to 2018, a population-based cross-sectional study. Dietary magnesium intake was assessed using 24-hour diet recalls. Atherosclerotic lesions in the young adult population were predicted by the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) score that was based on age, sex, smoking status, lipids, blood pressure, and obesity. Information on cardiovascular disease (CVD) risk factors including hypertension, non-HDL-C dyslipidemia, and diabetes was also collected. We used multivariable logistic analysis models to test the association between magnesium intake levels and the PDAY score and CVD risk factors, respectively, after adjusting for several potential confounding factors.

RESULTS

7,244 eligible participants were included in the analysis. The magnesium intake level was classified into three categories based on the tertile distribution in the population (i.e., ≤ 224, 225-340, and ≥ 341 mg/day). Compared with the lowest tertile, the multivariable-adjusted odds ratio (OR) and 95% confidence interval (95% CI) for the PDAY score were 0.83 (95% CI, 0.72 to 0.96) and 0.60 (95% CI, 0.49 to 0.74) in the second and the third tertiles of magnesium intake, respectively (P value for trend < 0.001), and there was a negative dose-response relationship (test for trend P value < 0.001). In addition, the highest dietary magnesium intake was significantly inverse associated with non-HDL-C dyslipidemia compared with the lowest magnesium intake (OR = 0.65; 95% CI, 0.46 to 0.91).

CONCLUSIONS

Dietary magnesium intake is inversely associated with the risk of future cardiovascular events assessed by the PDAY score and non-HDL-C dyslipidemia in young adulthood years.

Beyond Numbers: How Biochemical Parameters Can Predict Outcomes in Chronic Kidney Disease Patients on Maintenance Hemodialysis

Introduction The treatment and management of patients undergoing maintenance hemodialysis (MHD) requires constant evaluation through the assessment of biochemical markers. This is necessary for treatment, to prevent progression to complications such as mineral bone disease, and to improve quality of life. We aimed to study the biochemical profile of patients with chronic kidney disease (CKD) grades 4 and 5 on MHD, identify markers altered due to different etiologies, duration of illness, and duration of hemodialysis, and create a panel of markers that can be useful in planning better management. Methods All consecutive patients attending the dialysis unit of ESIC Super Speciality Hospital with CKD grade 4 or grade 5 on MHD between 2019 and 2020 were recruited. A detailed clinical history and demographic profile were taken, and blood samples were collected from the patients during follow-up visits in plain and EDTA (ethylenediamine tetraacetic acid) tubes for analysis. Results A total of 312 patients (22.1% females and 77.9% males.) with a mean age of 49.74 ± 11.49 years were recruited. In the study population, diabetic nephropathy (DN) (17%) and hypertensive nephropathy (48.7%) were the two most prevalent causes of CKD. The majority (64%) of the patients were on MHD three times a week. The range of estimated glomerular filtration rate (eGFR) (ml/min/1.73 m2) at the time of initiation of MHD was 2.9-26.8 according to the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula. The mean duration of MHD was 51.58 months, with a mortality rate of 5.9% during the follow-up period (3-108 months). Conclusion Optimal selection and combination of biochemical tests will help in ascertaining the adequacy of management, progress of disease, or complications in MHD patients. This in turn will help guide the clinicians in effectively using these markers in their day-to-day practice.

Inquiry of the Metabolic Traits in Relationship with Daily Magnesium Intake: Focus on Type 2 Diabetic Population

Magnesium (Mg), an essential nutrient with a wide area of physiological roles, stands as a cofactor in over 600 enzymatic reactions involved in the synthesis of proteins and nucleic acids, DNA repair, neuromuscular functions, neuronal transmission, cardiac rhythm regulation, and the modulation of metabolic pathways, as well as acting as a natural blocker for the calcium channels. Our objective was to highlight the most recent clinical data with respect to daily Mg intake (DMI) and metabolic traits, particularly type 2 diabetes mellitus (DM). This was a PubMed-based review of the English-language medical papers across different key terms of search; the time frame was from January 2019 until April 2024. We included (clinically relevant) original studies and excluded cases reports, series, reviews, editorials, opinion, experimental studies, and non-human data as well as studies that did not specifically assessed DMI and only provided assays of serum Mg, studies on patients diagnosed with type 1 or secondary DM. A total of 30 studies were included and we organized the key findings into several sections as follows. Studies investigating DMI in relationship with the adherence to local recommendations in diabetic subjects (n = 2, one transversal and another retrospective cohort; N = 2823) found that most of them had lower DMI. Deficient DMI was correlated with the risk of developing/having DM across five studies (n = 5, one prospective and four of cross-sectional design; N = 47,166). An inverse correlation between DMI and DM prevalence was identified, but these data are presented amid a rather heterogeneous spectrum. Four novel studies (N = 7279) analysed the relationship between DMI and DM control according to various methods (HbA1c, fasting and postprandial glycaemia, and insulin); the association may be linear in diabetic subjects only at certain levels of DMI; additionally, the multifactorial influence on HBA1c should take into consideration this dietary determinant, as well, but there are no homogenous results. Three studies concerning DMI and diabetic complications (one cross-sectional, one prospective, and another case-control study) in terms of retinopathy (n = 1, N = 3794) and nephropathy (n = 2, N = 4805) suggested a lower DMI was associated with a higher risk of such complications. Additionally, two other studies (one prospective and one retrospective cohort) focused on mortality (N = 6744), which, taking only certain mortality indicators into consideration, might be decreased in the subgroups with a higher DMI. Seven studies (N = 30,610) analysed the perspective of DMI in the general population with the endpoint of different features amid glucose profile, particularly, insulin resistance. Concerning HOMA-IR, there were three confirmatory studies and one non-confirmatory, while fasting plasma glucose was highlighted as inversely correlated with a DMI (n = 1). The highest level of evidence regarding Mg supplementation effects on glucose metabolism stands on seven randomised controlled trials (N = 350). However, the sample size was reduced (from 14 to 86 individuals per study, either diabetic or pre-diabetic) and outcomes were rather discordant. These clinical aspects are essential from a multidisciplinary perspective and further trials are mandatory to address the current areas of discordant results.

Peritoneal dialysis fluids

There have been significant advances in the understanding of peritoneal dialysis (PD) in the last 40 years, and uptake of PD as a modality of kidney replacement therapy is increasing worldwide. PD fluids, therefore, remains the lifeline for patients on this treatment. Developing these fluids to be efficacious in solute clearance and ultrafiltration, with minimal adverse consequences to peritoneal membrane health and systemic effects is a key requirement. Since the first PD fluid produced in 1959, modifications to PD fluids have been made. Nonetheless, the search for that ideal PD fluid remains elusive. Understanding the components of PD fluids is a key aspect of optimizing the successful delivery of PD, allowing for individualized PD prescription. Glucose remains an integral component of PD fluids; however, its deleterious effects continue to be the impetus for the search of an alternative osmotic agent, and icodextrin remains the main alternative. More biocompatible PD fluids have been developed and have shown benefits in preserving residual kidney function. However, high cost and reduced accessibility remain deterrents to its widespread clinical use in many countries. Large-scale clinical trials are necessary and very much awaited to improve the narrow spectrum of PD fluids available for clinical use.

Regulatory effects of nutritional and metabolic disorders on vascular calcification in chronic kidney disease: a narrative review

Background and Objective

Vascular calcification (VC) is common in chronic kidney disease (CKD) patients and is associated with poor cardiovascular outcomes. This study aims to review nutritive pro-calcifying factors of CKD.

Methods

Electronic databases (PubMed, Embase, and the Cochrane Central Register of Controlled Trials) were searched from 2001 as at July 26, 2022, to select and summarize the basic and clinical studies reporting the effects of malnutrition or metabolic disorders on VC in CKD and the evolving treatments for these nutrient metabolic disorders.

Key Content and Findings

Hyperphosphatemia, calcium load, hypomagnesemia, iron deficiency, lipoprotein(a) abnormalities, protein malnutrition, and vitamin K deficiency secondary to CKD were closely associated with the occurrence and development of VC. Elevated phosphate and calcium levels were essential contributors to VC, yet current phosphate binders with good phosphate-lowering effects had not been shown to delay VC progression in CKD, and it remained challenging on how to identify and prevent calcium overload. Magnesium supplementation was the most promising treatment for mitigating VC, as supported by in vitro and in vivo studies and clinical trials. Correction of iron and vitamin K deficiency might contribute to VC attenuation, yet there was a lack of clinical evidence on CKD patients.

Conclusions

This review highlighted the effects of nutrient metabolism disorders on CKD-VC, and additional studies are needed to further address optimal nutrition strategies for mitigating VC in CKD.

Lower serum magnesium is a predictor of left ventricular hypertrophy in patients on dialysis

PURPOSE

Left ventricular hypertrophy (LVH) represents one of the main risk factors for cardiovascular mortality in dialysis patients. Low serum magnesium Mg is related with increased mortality in general and dialysis population. Aim of our study was to evaluate the association of Mg with LVH and cardiac geometry in dialysis patients.

METHODS

Hemodialysis (HD) and peritoneal dialysis (PD) patients from nine nephrology departments were included. Echocardiographic LVH was defined by LV mass index > 95 g/m² in women and > 115 g/m² in men. Four LV geometric patterns were defined: normal, concentric remodeling, eccentric LVH and concentric LVH. Demographic and laboratory data were collected.

RESULTS

133 patients (68 HD, 65 PD) with a median age of 63 years (IQR 52-74) were studied. Mg correlated positively with creatinine, HDL and negatively with CRP levels and BMI. There were no significant differences in Mg between the modality groups. 80 patients presented LVH (43 HD and 37 PD patients). Patients with LVH were older (median age 68 vs 55 years, p < 0.001), with higher BMI (median 26.9 vs 24.7 kg/m², p = 0.009), had a history of PVD or CAD (55% vs 30.2%, p = 0.003), had higher pulse pressure (median 60 vs 50, p = 0.017), MIS score (median 5 vs 4, p = 0.011), lower albumin (median 3.5 vs 3.8 g/dl, p = 0.011) and Mg levels (median 2.1 vs 2.4 mg/dl, p < 0.001). In univariate analysis age, CVD comorbidities, pulse pressure, CRP, BMI, albumin, Mg, MIS and use of b-blockers or calcium blockers were LVH predictors. In multivariate analysis, Mg was an independent predictor of LVH, adjusted for age, MIS and b-blockers. Considering LV geometry, lower Mg levels were mainly correlated with concentric LVH.

CONCLUSION

Low serum magnesium levels seem to be an independent factor for LVH in hemodialysis and peritoneal dialysis patients.

Long non-coding RNAs at the crossroad of vascular smooth muscle cell phenotypic modulation in atherosclerosis and neointimal formation

Despite extraordinary advances in the comprehension of the pathophysiology of atherosclerosis and the employment of very effective treatments, cardiovascular diseases are still a major cause of mortality and represent a large share of health expenditure worldwide. Atherosclerosis is a disease affecting the medium and large arteries, which consists of a progressive accumulation of fatty substances, cellular waste products and fibrous elements, which culminates in the buildup of a plaque obstructing the blood flow. Endothelial dysfunction represents an early pathological event, favoring immune cells recruitment and triggering local inflammation. The release of inflammatory cytokines and other signaling molecules stimulates phenotypic modifications in the underlying vascular smooth muscle cells, which, in physiological conditions, are responsible for the maintenance of vessels architecture while regulating vascular tone. Vascular smooth muscle cells are highly plastic and may respond to disease stimuli by de-differentiating and losing their contractility, while increasing their synthetic, proliferative, and migratory capacity. This phenotypic switching is considered a pathological hallmark of atherogenesis and is ruled by the activation of selective gene programs. The advent of genomics and the improvement of sequencing technologies deepened our knowledge of the complex gene expression regulatory networks mediated by non-coding RNAs, and favored the rise of innovative therapeutic approaches targeting the non-coding transcriptome. In the context of atherosclerosis, long non-coding RNAs have received increasing attention as potential translational targets, due to their contribution to the molecular dynamics modulating the expression of vascular smooth muscle cells contractile/synthetic gene programs. In this review, we will focus on the most well-characterized long non-coding RNAs contributing to atherosclerosis by controlling expression of the contractile apparatus and genes activated in perturbed vascular smooth muscle cells.

Dietary metal intake and the prevalence of erectile dysfunction in US men: Results from National Health and Nutrition Examination Survey 2001-2004

BACKGROUND

Erectile dysfunction (ED) mainly affects men over 40 years of age and is a common clinical condition. In addition to hypertension and diabetes, environment, and lifestyle are also significantly associated with erectile dysfunction. The relationship between dietary trace metal intake and ED has not been studied.

MATERIALS AND METHODS

Data on participants were obtained from the National Health and Nutrition Examination Survey for this study, and those with incomplete information on clinical variables were excluded. Dose-response curve analysis was used to investigate the relationship between dietary trace metal intake and ED prevalence. Multivariate logistic regression analysis was used to adjust for confounders to further investigate the relationship between dietary trace metal intake and ED prevalence. 1:1 propensity score matching (PSM) was performed to adjust for differences between clinical variables for data reanalysis to confirm the reliability of the results.

RESULTS

A total of 3,745 individuals were included in the study, including 1096 ED patients and 2,649 participants without ED. Dietary intake of trace metals (Mg, Zn, Cu, and Se) was significantly higher in participants without ED than in ED patients (all P < 0.001). Dose-response curve analysis showed a significant negative association between these dietary metal intakes and ED prevalence (all P < 0.001). Multivariate logistic regression analysis adjusted for confounders (age, education, BMI, annual household income, hypertension, diabetes, marital status, race, and current health status) revealed that increased dietary metal intake reduced the odds ratio of ED. 1:1 PSM reanalysis further confirmed the validity of the results.

CONCLUSION

Increasing dietary intake of trace metals (magnesium, zinc, copper, and selenium) within the upper limit is beneficial in reducing the prevalence of ED.

The prognostic impact of magnesium in acute heart failure is different according to the presence of diabetes mellitus

Background

Hypermagnesemia predicts mortality in chronic heart failure (HF); however, in acute HF, magnesium does not seem to be outcome-associated. Diabetes mellitus (DM) frequently associates with altered magnesium status. We hypothesized that DM might influence the prognostic impact of magnesium in acute HF.

Methods

This is a retrospective cohort study of hospitalized patients with acute HF. Patients without data on admission serum magnesium were excluded. Follow-up: 1 year from hospital admission. Primary end point: all-cause mortality. Patients were divided according to median serum magnesium (1.64 mEq/L). The Kaplan-Meier survival method was used to determine survival curves according to magnesium levels. The analysis was stratified according to the presence of DM. A multivariable Cox regression analysis was used to study the prognostic impact of magnesium.

Results

We studied 606 patients. The mean age was 76 ± 12 years, 44.1% were male, 50.7% had DM, and 232 (38.3%) died during follow-up. Median magnesium was 1.64 (1.48-1.79) mEq/L. Patients with magnesium ≥1.64 mEq/L had higher 1-year mortality [141 (46.4%) vs 91 (30.1%), P < .001]. After adjustments for age, sex, history of atrial fibrillation, systolic blood pressure, heart rate, ischemic etiology, B-type natriuretic peptide, estimated glomerular filtration rate, alcohol consumption, antihyperglycaemic agents or glycated hemoglobin, admission glycemia, New York Heart Association class IV, and severe left ventricle systolic dysfunction, serum magnesium ≥1.64 mEq/L was associated with higher mortality only in patients with DM: HR 1.89 (95% confidence interval: 1.19-3.00), P = .007, and 1.27 (95% confidence interval: 0.83-1.94) and P = .26 for non-DM patients. The results were similar if magnesium was analyzed as a continuous variable. Per 0.1 mEq/L increase in magnesium levels, patients with DM had 13% increased risk of 1-year mortality.

Conclusions

Higher magnesium levels were associated with worse prognosis only in HF patients with DM.

Magnesium in renal fibrosis

PURPOSE

Renal fibrosis (RF) is the main pathological feature of chronic kidney disease (CKD). The main focus of research on treatment for CKD is to develop strategies that delay or prevent RF from progressing to end-stage renal disease (ESRD). Inflammation and oxidative stress occur during all stages of CKD. The magnesium cation (Mg²⁺) can reduce inflammation and oxidative stress, regulate apoptosis, and improve RF, and magnesium-based therapies are promising new treatments that can prevent RF. We reviewed the current evidence on the effects of magnesium in RF and examined the possible mechanism of magnesium in delaying RF.

METHODS

We searched PubMed, Web of Science, and EMBASE for articles on magnesium and fibrosis, with a focus on magnesium and RF.

RESULTS

Inflammation, oxidative stress, and apoptosis are related to the occurrence of CKD. Previous research showed that Mg²⁺ inhibits the differentiation of inflammatory cells, down-regulates the production of inflammatory cytokines, reduces inflammation, and reduces the production of reactive oxygen species (ROS) and oxidative stress. In addition, Mg²⁺ also regulates apoptosis and protects renal tubular function. Magnesium may also regulate TRPM6/7, promote the secretion of klotho protein and improve renal fibrosis. Therefore, Mg²⁺ can protect the kidney from damage and slow down the progression of RF through many molecular and cellular effects. Some of the anti-fibrotic effects of Mg²⁺ may be related to its antagonism of intracellular Ca²⁺.

CONCLUSION

Magnesium may prevent the progression of renal fibrosis and delay CKD by reducing renal inflammation and oxidative stress, and by regulating fibrosis-related signaling pathways and cytokines.

Impact of Post-Transplantation Hypomagnesemia on Long-Term Graft and Patient Survival after Transplantation

BACKGROUND

Post-transplant hypomagnesemia is commonly observed among patients prescribed calcineurin inhibitor (CNIs).

METHODS

We conducted a retrospective single-center analysis (2000-2013, N = 726) to examine the association of hypomagnesemia with long-term patient and allograft outcomes in kidney transplant recipients. A median serum magnesium (Mg) level of all measured Mg levels from 1 month to 1 year posttransplant was calculated.

RESULTS

For every increase in Mg of 0.1 mg/dL, the risk for either graft loss or death, overall mortality, and death with a functioning graft increased by 11%, 14%, and 12%, respectively (p < 0.01). In a multivariate model, patients with median Mg level ≥1.7 mg/dL had a reduced overall survival rate (HR 1.57, 95% CI: 1.04-2.38, p = 0.033) compared to those with median Mg level <1.7 mg/dL. This association was observed in subgroups of patients above 60 years old, in those who had a slow graft function (SGF) and in females.

CONCLUSIONS

Posttransplant hypomagnesemia is associated with better patient and allograft survival up to 10 years posttransplant. This relationship remained significant after accounting for baseline allograft function, presence of SGF and CNI trough levels.

Fibroblast growth factor 23 is independently associated with renal magnesium handling in patients with chronic kidney disease

BACKGROUND

Disturbances in magnesium homeostasis are common in patients with chronic kidney disease (CKD) and are associated with increased mortality. The kidney is a key organ in maintaining normal serum magnesium concentrations. To this end, fractional excretion of magnesium (FEMg) increases as renal function declines. Despite recent progress, the hormonal regulation of renal magnesium handling is incompletely understood. Fibroblast Growth Factor 23 (FGF23) is a phosphaturic hormone that has been linked to renal magnesium handling. However, it has not yet been reported whether FGF23 is associated with renal magnesium handling in CKD patients.

METHODS

The associations between plasma FGF23 levels, plasma and urine magnesium concentrations and FEMg was investigated in a cross-sectional cohort of 198 non-dialysis CKD patients undergoing renal biopsy.

RESULTS

FGF23 was significantly correlated with FEMg (Pearson's correlation coefficient = 0.37, p<0.001) and urinary magnesium (-0.14, p=0.04), but not with plasma magnesium. The association between FGF23 and FEMg remained significant after adjusting for potential confounders, including estimated glomerular filtration rate (eGFR), parathyroid hormone and 25-hydroxyvitamin D.

CONCLUSIONS

We report that plasma FGF23 is independently associated with measures of renal magnesium handling in a cohort of non-dialysis CKD patients. A potential causal relationship should be investigated in future studies.

Associations between the serum magnesium and all-cause or cardiovascular mortality in chronic kidney disease and end-stage renal disease patients: A meta-analysis

BACKGROUND

Some studies have found that hypomagnesemia is associated with vascular calcification, atherosclerosis, and cardiovascular disease, which may lead to increased mortality in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD) who need to maintain hemodialysis (HD). However, the conclusion of these studies remain controversial.

METHODS

Relevant literature was retrieved from the database of Cochrane library, PubMed, EMBASE, and CNKI until December 2020, without any language restrictions. The data was analyzed using the Stata 12.0 software.

RESULTS

A total of 31 studies were included, involving 205436 participants. The results showed that after multivariable adjusted, hypomagnesemia was significant associated with the risk of all-cause mortality in patients with CKD and end-stage renal disease (ESRD) (hazard ratios [HR] 1.955; 95% confidence interval (95% CI) 1.511-2.528; P = .000; hypomagnesemia vs normal magnesium or hypermagnesemia). In contrast, in patients with CKD and ESRD, hypermagnesemia was negatively correlated with all-cause mortality (HR 0.873; 95% CI 0.793-0.960; P = .005) (per unit increase). Moreover, in the adjusted model, it was observed that hypermagnesemia was significantly associated with a reduced risk of cardiovascular death (HR 0.598; 95% CI 0.094-1.102, P = .020). In addition, subgroup analysis found that hypomagnesemia was closely related to the increase of all-cause mortality in HD patients (HR 1.799; 95% CI 1.375-2.354; P = .000) (hypomagnesemia vs normal magnesium or hypermagnesemia).

CONCLUSION

Our results show that hypomagnesemia is significantly associated with cardiovascular and all-cause mortality in maintenance HD patients. Further studies should be conducted to evaluate the benefits of magnesium correction in maintenance dialysis patients with hypomagnesemia.

Renal Magnesium Handling: A Comparison Between Dogs With Chronic Kidney Disease and Healthy Elderly Dogs

Chronic kidney disease (CKD) and aging are known to possibly cause a progressive reduction in glomerular filtration rate, which may be associated with an increase in fractional excretion of electrolytes due to an adaptive response of the remaining functioning nephrons. However, the behavior of magnesium excretion has not been studied in CKD and healthy elderly dogs. The objective was to evaluate the fractional excretion of magnesium (FEMg) in dogs with (CKD) compared to healthy elderly dogs. Sixteen healthy elderly dogs and 43 dogs with CKD were divided into 3 groups (CKD 2 [n = 14], CKD 3 [n = 17], CKD 4 [n = 12]), in accordance with the current International Renal Interest Society (IRIS) criteria that were used in this study. Blood samples were obtained by jugular venipuncture and urine samples were obtained by cystocentesis. The FEMg was evaluated at a single time point in both urine and blood samples. FEMg was significantly higher in dogs with CKD compared to healthy elderly dogs, especially in advanced stages. This preliminary study demonstrates that FEMg may be altered in dogs with CKD. Further research is warranted to elucidate magnesium's potential role in cardiovascular and arterial calcification in dogs with CKD as observed in humans with CKD.

High Intakes of Bioavailable Phosphate May Promote Systemic Oxidative Stress and Vascular Calcification by Boosting Mitochondrial Membrane Potential-Is Good Magnesium Status an Antidote?

Chronic kidney disease is characterized by markedly increased risk for cardiovascular mortality, vascular calcification, and ventricular hypertrophy, and is associated with increased systemic oxidative stress. Hyperphosphatemia, reflecting diminished glomerular phosphate (Pi) clearance, coupled with a compensatory increase in fibroblast growth factor 23 (FGF23) secretion are thought to be key mediators of this risk. Elevated serum and dietary Pi and elevated plasma FGF23 are associated with increased cardiovascular and total mortality in people with normal baseline renal function. FGF23 may mediate some of this risk by promoting cardiac hypertrophy via activation of fibroblast growth factor receptor 4 on cardiomyocytes. Elevated serum Pi can also cause a profound increase in systemic oxidative stress, and this may reflect the ability of Pi to act directly on mitochondria to boost membrane potential and thereby increase respiratory chain superoxide production. Moreover, elevated FGF23 likewise induces oxidative stress in vascular endothelium via activation of NADPH oxidase complexes. In vitro exposure of vascular smooth muscle cells to elevated Pi provokes an osteoblastic phenotypic transition that is mediated by increased mitochondrial oxidant production; this is offset dose-dependently by increased exposure to magnesium (Mg). In vivo, dietary Mg is protective in rodent models of vascular calcification. It is proposed that increased intracellular Mg opposes Pi's ability to increase mitochondrial membrane potential; this model could explain its utility for prevention of vascular calcification and predicts that Mg may have a more global protective impact with regard to the direct pathogenic effects of hyperphosphatemia.

Nutraceutical, Dietary, and Lifestyle Options for Prevention and Treatment of Ventricular Hypertrophy and Heart Failure

Although well documented drug therapies are available for the management of ventricular hypertrophy (VH) and heart failure (HF), most patients nonetheless experience a downhill course, and further therapeutic measures are needed. Nutraceutical, dietary, and lifestyle measures may have particular merit in this regard, as they are currently available, relatively safe and inexpensive, and can lend themselves to primary prevention as well. A consideration of the pathogenic mechanisms underlying the VH/HF syndrome suggests that measures which control oxidative and endoplasmic reticulum (ER) stress, that support effective nitric oxide and hydrogen sulfide bioactivity, that prevent a reduction in cardiomyocyte pH, and that boost the production of protective hormones, such as fibroblast growth factor 21 (FGF21), while suppressing fibroblast growth factor 23 (FGF23) and marinobufagenin, may have utility for preventing and controlling this syndrome. Agents considered in this essay include phycocyanobilin, N-acetylcysteine, lipoic acid, ferulic acid, zinc, selenium, ubiquinol, astaxanthin, melatonin, tauroursodeoxycholic acid, berberine, citrulline, high-dose folate, cocoa flavanols, hawthorn extract, dietary nitrate, high-dose biotin, soy isoflavones, taurine, carnitine, magnesium orotate, EPA-rich fish oil, glycine, and copper. The potential advantages of whole-food plant-based diets, moderation in salt intake, avoidance of phosphate additives, and regular exercise training and sauna sessions are also discussed. There should be considerable scope for the development of functional foods and supplements which make it more convenient and affordable for patients to consume complementary combinations of the agents discussed here. Research Strategy: Key word searching of PubMed was employed to locate the research papers whose findings are cited in this essay.

Intestinal Chelators, Sorbants, and Gut-Derived Uremic Toxins

Chronic kidney disease (CKD) is a highly prevalent condition and is associated with a high comorbidity burden, polymedication, and a high mortality rate. A number of conventional and nonconventional risk factors for comorbidities and mortality in CKD have been identified. Among the nonconventional risk factors, uremic toxins are valuable therapeutic targets. The fact that some uremic toxins are gut-derived suggests that intestinal chelators might have a therapeutic effect. The phosphate binders used to prevent hyperphosphatemia in hemodialysis patients act by complexing inorganic phosphate in the gastrointestinal tract but might conceivably have a nonspecific action on gut-derived uremic toxins. Since phosphorous is a major nutrient for the survival and reproduction of bacteria, changes in its intestinal concentration may impact the gut microbiota’s activity and composition. Furthermore, AST-120 is an orally administered activated charcoal adsorbent that is widely used in Asian countries to specifically decrease uremic toxin levels. In this narrative review, we examine the latest data on the use of oral nonspecific and specific intestinal chelators to reduce levels of gut-derived uremic toxins.

Serum magnesium, bone-mineral metabolism markers and their interactions with kidney function on subsequent risk of peripheral artery disease: the Atherosclerosis Risk in Communities Study

BACKGROUND

Few studies have investigated the association of magnesium levels with incident peripheral artery disease (PAD) despite emerging evidence of magnesium contributing to vascular calcification. Moreover, no data are available on whether the magnesium-PAD relationship is independent of or modified by kidney function.

METHODS

A cohort of 11 839 participants free of PAD in the Atherosclerosis Risk in Communities Study at Visit 2 (1990-92) was studied. We investigated the association of serum magnesium and other bone-mineral metabolism markers [calcium, phosphorus, intact parathyroid hormone (iPTH) and intact fibroblast growth factor-23] with incident PAD using multivariable Cox proportional hazards regression.

RESULTS

Over a median of 23 years, there were 471 cases of incident PAD. The hazard ratio for incident PAD in Quartile 1 (<1.5 mEq/L) versus Quartile 4 (>1.7 mEq/L) of magnesium was 1.96 (95% confidence interval 1.40-2.74) after adjustment for potential confounders. Lower magnesium levels were associated with greater incidence of PAD, particularly in those with estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 (n = 11 606). In contrast, the association was largely flat in those with eGFR <60 mL/min/1.73 m2 (n = 233) with P-for-interaction 0.03. Among bone-mineral metabolism markers, only higher iPTH showed an interaction with kidney function (P-for-interaction 0.01) and iPTH >65 pg/mL was significantly related to PAD only in those with eGFR <60 mL/min/1.73 m2.

CONCLUSIONS

Lower magnesium was independently associated with incident PAD, but this association was significantly weaker in those with reduced kidney function. In contrast, higher iPTH levels were particularly related to PAD risk in this clinical population.

Cardiovascular Calcification in Chronic Kidney Disease-Therapeutic Opportunities

Patients with chronic kidney disease (CKD) are highly susceptible to cardiovascular (CV) complications, thus suffering from clinical manifestations such as heart failure and stroke. CV calcification greatly contributes to the increased CV risk in CKD patients. However, no clinically viable therapies towards treatment and prevention of CV calcification or early biomarkers have been approved to date, which is largely attributed to the asymptomatic progression of calcification and the dearth of high-resolution imaging techniques to detect early calcification prior to the 'point of no return'. Clearly, new intervention and management strategies are essential to reduce CV risk factors in CKD patients. In experimental rodent models, novel promising therapeutic interventions demonstrate decreased CKD-induced calcification and prevent CV complications. Potential diagnostic markers such as the serum T50 assay, which demonstrates an association of serum calcification propensity with all-cause mortality and CV death in CKD patients, have been developed. This review provides an overview of the latest observations and evaluates the potential of these new interventions in relation to CV calcification in CKD patients. To this end, potential therapeutics have been analyzed, and their properties compared via experimental rodent models, human clinical trials, and meta-analyses.

Impact of admission serum magnesium levels on long-term mortality in hospitalized patients

BACKGROUND

The impact of admission serum magnesium on long-term mortality in hospitalized patients was unclear. This study aimed to assess the long-term mortality risk based on admission of serum magnesium in hospitalized patients.

METHODS

This was a retrospective cohort study conducted at a tertiary referral hospital. We included all adult patients admitted to Mayo Clinic Hospital, Minnesota, between 1 January 2009 and 31 December 2013, who had available admission serum magnesium. We categorized serum magnesium into ≤1.4, 1.5-1.6, 1.7-1.8, 1.9-2.0, 2.1-2.2, ≥2.3 mg/dL. We estimated the 1-year mortality risk based on various admission serum magnesium levels using Kaplan-Meier plot and assessed the association of admission serum magnesium with 1-year mortality using Cox proportional hazard analysis. We selected serum magnesium of 1.7-1.8 mg/dL as the reference group for mortality comparison.

RESULTS

We included a total of 65,974 patients, with a mean admission serum magnesium of 1.9 ± 0.3 mg/dL in this study. The 1-year mortality was 15.7%, 15.8%, 15.5%, 16.7%, 19.0%, and 25.6% in admission serum magnesium of ≤1.4, 1.5-1.6, 1.7-1.8, 1.9-2.0, 2.1-2.2, ≥2.3 mg/dL, respectively (p < 0.001). After adjustment for confounders, admission serum magnesium of 1.9-2.0, 2.1-2.2, and ≥2.3 mg/dL were significantly associated with increased 1-year mortality compared with magnesium of 1.7-1.8 mg/dL with adjusted HR of 1.09 (95% CI 1.02-1.15), 1.22 (95% CI 1.14-1.30), and 1.55 (95% CI 1.45-1.55), respectively. There was no significant difference in 1-year mortality risk between low serum magnesium ≤1.6 mg/dL and magnesium of 1.7-1.8 mg/dL.

CONCLUSION

Hypermagnesemia, but not hypomagnesemia, at the time of hospital admission was associated with increased 1-year mortality among hospitalized patients.

Serum magnesium, mortality and disease progression in chronic kidney disease

Introduction

Magnesium disorders are commonly encountered in chronic kidney disease (CKD) and are typically a consequence of decreased kidney function or frequently prescribed medications such as diuretics and proton pump inhibitors. While hypomagnesemia has been linked with increased mortality, the association between elevated magnesium levels and mortality is not clearly defined. Additionally, associations between magnesium disorders, type of death, and CKD progression have not been reported. Therefore, we studied the associations between magnesium levels, CKD progression, mortality, and cause specific deaths in patients with CKD.

Methods

Using the Cleveland Clinic CKD registry, we identified 10,568 patients with estimated Glomerular Filtration Rate (eGFR) between 15 and 59 ml/min/1.73 m² in this range for a minimum of 3 months with a measured magnesium level. We categorized subjects into 3 groups based on these magnesium levels (≤ 1.7, 1.7–2.6 and > 2.6 mg/dl) and applied cox regression modeling and competing risk models to identify associations with overall and cause-specific mortality. We also evaluated the association between magnesium level and slope of eGFR using mixed models.

Results

During a median follow-up of 3.7 years, 4656 (44%) patients died. After adjusting for relevant covariates, a magnesium level < 1.7 mg/dl (vs. 1.7–2.6 mg/dl) was associated with higher overall mortality (HR = 1.14, 95% CI: 1.04, 1.24), and with higher sub-distribution hazards for non-cardiovascular non-malignancy mortality (HR = 1.29, 95% CI: 1.12, 1.49). Magnesium levels > 2.6 mg/dl (vs. 1.7–2.6 mg/dl) was associated with a higher risk of all-cause death only (HR = 1.23, 95% CI: 1.03, 1.48). We found similar results when evaluating magnesium as a continuous measure. There were no significant differences in the slope of eGFR across all three magnesium groups (p = 0.10).

Conclusions

In patients with CKD stage 3 and 4, hypomagnesemia was associated with higher all-cause and non-cardiovascular non-malignancy mortality. Hypermagnesemia was associated with higher all-cause mortality. Neither hypo nor hypermagnesemia were associated with an increased risk of CKD progression.

Metformin and Micronutrient Status in Type 2 Diabetes: Does Polypharmacy Involving Acid-Suppressing Medications Affect Vitamin B12 Levels?

Metformin is the first-choice drug in uncomplicated type 2 diabetes (T2DM) and is effective in improving glycaemic control. It is the most widely prescribed oral antidiabetic medicine and has a good safety profile. However, there is an abundance of evidence that metformin use is associated with decreased Vitamin B12 status, though the clinical implications of this in terms of increased risk of diabetic peripheral neuropathy are debated. There is growing evidence that other B vitamins, vitamin D and magnesium may also be impacted by metformin use in addition to alterations to the composition of the microbiome, depending on the dose and duration of therapy. Patients using metformin for prolonged periods may, therefore, need initial screening with intermittent follow-up, particularly since vitamin B₁₂ deficiency has similar symptoms to diabetic neuropathy which itself affects 40-50% of patients with T2DM at some stage. Among patients with T2DM, 40% are reported to experience symptomatic gastroesophageal reflux disease (GORD), of whom 70% use oral antidiabetic medications. The most common medications used to treat GORD are proton pump inhibitors (PPIs) and antagonists of histamine selective H₂ receptors (H₂RAs), both of which independently affect vitamin B₁₂ and magnesium status. Research indicates that co-prescribing metformin with either PPIs or H₂RAs can have further deleterious effects on vitamin B₁₂ status. Vitamin B12 deficiency related to metformin and polypharmacy is likely to contribute to the symptoms of diabetic neuropathy which may frequently be under-recognised. This review explores current knowledge surrounding these issues and suggests treatment strategies such as supplementation.

Hypomagnesemia and Short-Term Mortality in Elderly Maintenance Hemodialysis Patients

Background

The relationship between magnesium and mortality in hemodialysis patients has been evaluated in several prospective studies, but few have assessed the risk of all-cause mortality in elderly hemodialysis patients. The aim of this study was to evaluate the association between magnesium levels and the risk of cardiovascular and overall mortality in elderly maintenance hemodialysis patients.

Methods

This was a retrospective study, and patients undergoing maintenance hemodialysis were screened for eligibility at a single dialysis center between July and December 2016. Patients were divided into two groups based on their magnesium levels: a low magnesium level group and a high magnesium level group. Associations between magnesium level and risk of cardiovascular and all-cause mortality were analyzed with a Cox proportional hazards regression model.

Results

In total, 413 patients were included with a median follow-up period of 12 months. We found that compared to patients with high magnesium levels, those with low magnesium levels had significantly lower levels of hemoglobin, urea, creatinine, uric acid, phosphate, potassium, chloride, albumin, and spKt/V (p < 0.05 for each parameter). There was a strong correlation between the baseline mean serum magnesium concentration 1 year prior and the concentration 1 year later (r² = 0.519, p < 0.001). After adjustment for confounding factors, multivariate Cox proportional hazards analysis showed hypomagnesemia to be an independent predictor of all-cause and cardiovascular mortality in chronic hemodialysis patients. Furthermore, subgroup analysis was performed, revealing that serum magnesium levels were still strongly associated with all-cause mortality and cardiovascular mortality in patients older than 60 years, with HR values of 0.020 (95% CI 0.001-0.415) and 0.010 (95% CI 0.000-0.491), respectively. In addition, there were still significant associations between the serum magnesium level and all-cause mortality and cardiovascular mortality in elderly dialysis patients at the 6-month follow-up visit.

Conclusion

Our study indicates that lower serum magnesium levels are strongly associated with cardiovascular and all-cause mortality in maintenance hemodialysis patients, especially in the short term and in those who are elderly. Factors affecting serum magnesium concentrations in hemodialysis patients should be investigated, and correcting hypomagnesemia may benefit elderly hemodialysis patients.

Reversal of phosphate-induced ORAI1 expression, store-operated Ca2+ entry and osteogenic signaling by MgCl2 in human aortic smooth muscle cells

In chronic kidney disease, renal phosphate retention leads to hyperphosphatemia with subsequent vascular osteogenic signaling and calcification. Osteogenic signaling involves up-regulation of the transcription factors CBFA1, MSX2, and SOX9, as well as alkaline phosphatase (ALP), an enzyme stimulating calcification by degrading the calcification inhibitor pyrophosphate. Stimulation of osteogenic signaling and calcification by phosphate donor β-glycerophosphate in human aortic smooth muscle cells (HAoSMCs) is attenuated by MgCl₂, an effect mimicked by Ca²⁺-sensing receptor agonist GdCl₃. Most recent observations revealed that the effect of β-glycerophosphate on osteogenic signaling requires ORAI1, a Ca²⁺-channel accomplishing store-operated Ca²⁺-entry (SOCE), which is stimulated by Ca²⁺-sensor STIM1. The present study explored whether ORAI1 and/or STIM1 expression and, thus, SOCE and osteogenic signaling in HAoSMCs are sensitive to MgCl₂ and/or GdCl₃. To this end, transcript levels were estimated using q-RT-PCR, protein abundance with western blotting, cytosolic Ca²⁺-concentration ([Ca²⁺]_i) by Fura-2-fluorescence, and SOCE from increase of [Ca²⁺]_i following re-addition of extracellular Ca²⁺ after store depletion with thapsigargin (1  μM). As a result, 24 h exposure to β-glycerophosphate (2 mM) significantly enhanced transcript levels of ORAI1 and STIM1 as well as SOCE, effects significantly blunted or virtually abrogated by 1.5 mM MgCl₂ and by 50  μM GdCl₃. In conclusion, MgCl₂ and GdCl₃ are powerful inhibitors of ORAI1 and STIM1 expression and store-operated Ca²⁺-entry, effects affecting osteogenic signalling in vascular smooth muscle cells.

Anabolic effects of vitamin D and magnesium in aging bone

Decreased bone mass and an increased risk of bone fractures become more common with age. This condition is often associated with osteoporosis and is caused by an imbalance of bone resorption and new bone formation. Lifestyle factors that affect the risk of osteoporosis include alcohol, diet, hormones, physical activity, and smoking. Calcium and vitamin D are particularly important for the age-related loss of bone density and skeletal muscle mass, but other minerals, such as magnesium, also have an important role. Here, we summarize how optimal magnesium and vitamin D balance improve health outcomes in the elderly, the role of magnesium and vitamin D on bone formation, and the implications of widespread deficiency of these factors in the United States and worldwide, particularly in the elderly population.

Case report: extreme coronary calcifications and hypomagnesemia in a patient with a 17q12 deletion involving HNF1B

Background

17q12 deletion syndrome encompasses a broad constellation of clinical phenotypes, including renal magnesium wasting, maturity-onset diabetes of the young (MODY), renal cysts, genitourinary malformations, and neuropsychiatric illness. Manifestations outside of the renal, endocrine, and nervous systems have not been well described.

Case presentation

We report a 62-year-old male referred to the Undiagnosed Diseases Program (UDP) at the National Institutes of Health (NIH) who presented with persistent hypermagnesiuric hypomagnesemia and was found to have a 17q12 deletion. The patient exhibited several known manifestations of the syndrome, including severe hypomagnesemia, renal cysts, diabetes and cognitive deficits. Coronary CT revealed extensive coronary calcifications, with a coronary artery calcification score of 12,427. Vascular calcifications have not been previously reported in this condition. We describe several physiologic mechanisms and a review of literature to support the expansion of the 17q12 deletion syndrome to include vascular calcification.

Conclusion

Extensive coronary and vascular calcifications may be an extension of the 17q12 deletion phenotype, particularly if hypomagnesemia and hyperparathyroidism are prevalent. In patients with 17q12 deletions involving HNF1B, hyperparathyroidism and hypomagnesemia may contribute to significant cardiovascular risk.

Strategies for Phosphate Control in Patients With CKD

Hyperphosphatemia is a common complication in patients with chronic kidney disease (CKD), particularly in those requiring renal replacement therapy. The importance of controlling serum phosphate has long been recognized based on observational epidemiological studies that linked increased phosphate levels to adverse outcomes and higher mortality risk. Experimental data further supported the role of phosphate in the development of bone and cardiovascular diseases. Recent advances in our understanding of the mechanisms involved in phosphate homeostasis have made it clear that the serum phosphate concentration depends on a complex interplay among the kidneys, intestinal tract, and bone, and is tightly regulated by a complex endocrine system. Moreover, the source of dietary phosphate and the use of phosphate-based additives in industrialized foods are additional factors that are of particular importance in CKD. Not surprisingly, the management of hyperphosphatemia is difficult, and, despite a multifaceted approach, it remains unsuccessful in many patients. An additional issue is the fact that the supposedly beneficial effect of phosphate lowering on hard clinical outcomes in interventional trials is a matter of ongoing debate. In this review, we discuss currently available treatment approaches for controlling hyperphosphatemia, including dietary phosphate restriction, reduction of intestinal phosphate absorption, phosphate removal by dialysis, and management of renal osteodystrophy, with particular focus on practical challenges and limitations, and on potential benefits and harms.

Long noncoding RNAs in vascular smooth muscle cells regulate vascular calcification

Vascular calcification is characterized by the accumulation of hydroxyapatite crystals, which is a result of aberrant mineral metabolism. Although many clinical studies have reported its adverse effects on cardiovascular morbidity, the molecular mechanism of vascular calcification, especially the involvement of long noncoding RNAs (lncRNAs), is not yet reported. From the transcriptomic analysis, we discovered hundreds of lncRNAs differentially expressed in rat vascular smooth muscle cells (VSMCs) treated with inorganic phosphate, which mimics vascular calcification. We focused on Lrrc75a-as1 and elucidated its transcript structure and confirmed its cytoplasmic localization. Our results showed that calcium deposition was elevated after knockdown of Lrrc75a-as1, while its overexpression inhibited calcium accumulation in A10 cells. In addition, Lrrc75a-as1 attenuated VSMCs calcification by decreasing the expression of osteoblast-related factors. These findings suggest that Lrrc75a-as1 acts as a negative regulator of vascular calcification, and may serve as a possible therapeutic target in vascular calcification.

Serum magnesium, mortality, and cardiovascular disease in chronic kidney disease and end-stage renal disease patients: a systematic review and meta-analysis

BACKGROUND

Previous studies reported that magnesium deficiency was associated with vascular calcifications, atherosclerosis and cardiovascular disease, which might play an independent pathogenic role in chronic kidney disease (CKD) and end-stage renal disease (ESRD) patients. However, the results of these studies were somewhat underpowered and inconclusive.

METHODS

Literature was identified by searching PubMed, EMBASE, Web of Science and the Cochrane Central Register of Controlled Trials (CENTRAL). We included studies that investigated the association between serum magnesium with mortality risk in CKD and ESRD patients. Unadjusted and adjusted hazard ratios (HRs) with 95% confidence intervals (95% CIs) were pooled.

RESULTS

Twenty studies involving 200,934 participants were included, and the results showed that there was a strong association between hypomagnesemia and the risk of all-cause mortality in patients with CKD and ESRD (HR 1.32; 95% CI 1.19-1.47; p < 0.00001) (hypomagnesemia vs. normal magnesium or hypermagnesemia) after multivariable adjusted. On the contrary, hypermagnesemia was inversely associated with all-cause mortality in patients with CKD and ESRD (HR 0.86; 95% CI 0.79-0.94; p = 0.001) (per unit increase). Moreover, a significant association between hypermagnesemia and decreased risk of cardiovascular mortality was observed (HR 0.71; 95% CI 053-0.97, p = 0.03) in the adjusted model. In addition, subgroup analysis found that hypomagnesemia was strongly associated with increased all-cause mortality in hemodialysis patients (HR 1.29; 95% CI 1.12-1.50; p = 0.0005) (hypomagnesemia vs. normal magnesium or hypermagnesemia).

CONCLUSIONS

Our results indicate that hypomagnesemia is significantly associated with cardiovascular and all-cause mortality in patients with CKD and ESRD. Further studies evaluating benefits of magnesium correction in CKD and dialysis patients with hypomagnesemia should be performed.

Serum Magnesium after Kidney Transplantation: A Systematic Review

Magnesium (Mg) status has recently drawn close attention in chronic kidney disease and in kidney transplant recipients. This review aims to evaluate the body of evidence linking hypomagnesemia to clinical consequences in these specific populations. After a brief summary of the main mechanisms involved in Mg regulation and of Mg status in end-stage renal disease, the review focuses on the relationship between hypomagnesemia and cardiovascular risk in kidney transplant recipients. A body of evidence in recent studies points to a negative impact of hypomagnesemia on post-transplant diabetes mellitus (PTDM) and cardiovascular risk, which currently represent the main threat for morbidity and mortality in kidney transplantation. Deleterious biological mechanisms induced by hypomagnesemia are also discussed. While data analysis enables us to conclude that hypomagnesemia is linked to the development of PTDM, studies prospectively evaluating the impact of hypomagnesemia correction after kidney transplantation are still lacking and needed.

Y. Chiu D, Kalra PA, Green D. Prevalence and outcomes of proton pump inhibitor associated hypomagnesemia in chronic kidney disease

Background

Proton pump inhibitors (PPIs) are one of the most widely prescribed medications across the world. PPIs have been associated with significant electrolyte abnormalities including hypomagnesaemia. We explored the prevalence of PPI associated hypomagnesaemia (PPIH) in different Chronic Kidney Disease (CKD) stages, in different PPI agents, and the impact of PPIH on survival in CKD.

Methods

This was a subgroup analysis of the Salford Kidney Study, a prospective, observational, longitudinal study of non-dialysis CKD patients. Patients with outpatient magnesium samples obtained between 2002 and 2013 were included in the analysis. The prevalence hypomagnesaemia based on mean values over 12 months as well as ‘ever’ hypomagnesaemia were investigated.

Results

1,230 patients were included in this analysis, mean age 64.3± 32.3 years and mean eGFR 29.2±15.8 ml/min/1.73m². Mean serum magnesium in those on PPI was significantly lower than those not on PPI overall (0.85±0.10 mmolL^-1 versus 0.79±0.12 mmolL^-1 respectively, p<0.001). This finding was maintained at all CKD stages. The adjusted odds ratio (OR) for mean hypomagnesaemia in PPI use was 1.12 (95% CI 1.06–1.18) p = <0. ‘Ever hypomagnesaemia’ had an OR of 1.12 (95% CI 1.07–1.16) p = <0.001. The expected rise in serum magnesium with declining eGFR was not observed in those on a PPI but was seen in those not on PPI. There was no difference in serum magnesium between PPI drugs. Thiazide diuretics were also associated with hypomagnesaemia independent of PPI use. Cox regression analysis demonstrated no reduction in survival in patients with PPI associated hypomagnesaemia.

Conclusion

No specific PPI drugs show a favourable profile in regards of risk for hypomagnesaemia in CKD. Avoiding concurrent use of PPI and thiazide may be of value in patients with hypomagnesaemia.

Magnesium as a Calcification Inhibitor

Vascular calcification (VC) is associated with elevated cardiovascular mortality rates in patients with CKD. Recent clinical studies of patients with advanced CKD have observed an association between low serum magnesium (Mg) levels on one hand and elevated VC and cardiovascular mortality on the other. These findings have stimulated interest in understanding Mg's impact on CKD in general and the associated VC in particular. In vitro and preclinical in vivo data indicate that Mg has the potential to protect vascular smooth muscle cells against calcification via several different molecular mechanisms. Accordingly, data from pilot interventional studies in the clinic suggest that oral Mg supplementation reduces VC in patients with CKD. The present review provides an overview of our current understanding of the impact of Mg on the development of VC in patients with CKD.

Magnesium in Chronic Kidney Disease: Should We Care?

BACKGROUND

Magnesium (Mg) is an essential cation for multiple processes in the body. The kidney plays a major role in regulating the Mg balance. In a healthy individual, total-body Mg content is kept constant by interactions among intestine, bones and the kidneys.

SUMMARY

In case of chronic kidney disease (CKD), renal regulatory mechanisms may be insufficient to balance intestinal Mg absorption. Usually Mg remains normal; however, when glomerular filtration rate declines, changes in serum Mg are observed. Patients with end-stage renal disease on dialysis are largely dependent on the dialysate Mg concentration for maintaining serum Mg and Mg homeostasis. A low Mg is associated with several complications such as hypertension, and vascular calcification, and also associated with an increased risk for both cardiovascular disease (CVD) and non-CVD mortality. Severe hypermagnesaemia is known to cause cardiac conduction defects, neuromuscular effects and muscle weakness; a slightly elevated Mg has been suggested to be beneficial in patients with end-stage renal disease. Key Messages: The role of both low and high Mg, in general, but especially in relation to CKD and dialysis patients is discussed.

High magnesium prevents matrix vesicle-mediated mineralization in human bone marrow-derived mesenchymal stem cells via mitochondrial pathway and autophagy

Magnesium, as a physiological calcium antagonist, plays a vital role in the bone metabolism and the balance between magnesium and calcium is crucial in bone physiology. We recently demonstrated that matrix mineralization in human bone marrow-derived mesenchymal stem cells (hBMSCs) can be suppressed by high Mg²⁺ . However, a complete understanding of the mechanisms involved still remains to be elucidated. As mitochondrial calcium phosphate granules depletion manifests concurrently with the appearance of matrix vesicles (MVs) and autophagy are associated with matrix mineralization, we studied the effect of high extracellular Mg²⁺ on these pathways. Our results first demonstrated that high Mg²⁺ has a significant inhibitory effect on the generalization of extracellular mineral aggregates and the expression of collagen 1 along which the mineral crystals grow. Transmission electron microscope results showed that less amount of MVs were observed inside hBMSCs treated with high Mg²⁺ and high Mg²⁺ inhibited the release of MVs. In addition, high Mg²⁺ significantly suppressed mitochondrial Ca²⁺ accumulation. Autophagy is promoted as a response to osteogenesis of hBMSCs. High Mg²⁺ inhibited the level of autophagy upon osteogenesis and autophagy inhibitor 3-MA significantly suppressed mineralization. Exogenous ATP can reverse the inhibitory effect of high Mg²⁺ by increasing the level of autophagy. Taken together, our results indicate that high Mg²⁺ may modulate MVs-mediated mineralization via suppressing mitochondrial Ca²⁺ intensity and regulates autophagy of hBMSCs upon osteogenesis, resulting in decreased extracellular mineralized matrix deposition. Our results contribute to the understanding of the role of magnesium homeostasis in osteoporosis and the design of magnesium alloys.

Consumption of whole grains, fruit and vegetables is not associated with indices of renal function in the population-based longitudinal Doetinchem study

Emerging evidence suggests that diet and renal function are related. Little is known, however, about the association of consumption of whole grains, fruit and vegetables with urinary albumin:creatinine ratio (ACR) and changes in estimated glomerular filtration rate (eGFR). We investigated this in a population-based cohort aged 26-65 years. Data were from 3787 participants from the Doetinchem cohort study, who were examined ≥3 times, 5 years apart. Consumption of food groups was assessed at each round with a validated FFQ. GFR was estimated at each round from routinely measured cystatin C and creatinine using the Chronic Kidney Disease-Epidemiology (CKD-EPI) equation. ACR was measured at the last round. Generalised estimated equation models were performed to examine associations with changes in eGFR. Linear regression was used to examine associations with ACR. Adjustments were made for covariates related to lifestyle, biological factors and diet. Mean baseline eGFR was 104·5 (sd 13·7) and mean annual decline was -0·95 (sd 0·67) ml/min per 1·73 m2 over a 15-year follow-up. A trend was observed towards slightly less annual decline in eGFR among those with higher consumption of whole grains (P=0·06). This association, however, was attenuated and no longer significant in multivariate models (P=0·29). Consumption of fruit and vegetables was not associated with changes in eGFR and urinary ACR. In conclusion, consumption of whole grains, fruit and vegetables is not associated with changes in eGFR and mean ACR. As this was the first longitudinal study into this association in the general population, and as results are only partially in line with related studies, further research is recommended.

High Calcium-Magnesium Ratio in Hair Is Associated with Coronary Artery Calcification in Middle-Aged and Elderly Individuals

The interaction between calcium and magnesium as a risk modifier for cardiovascular disease (CVD) has been largely overlooked in previous studies, for the strict regulatory system in blood has been thought to keep such homeostatic interactions under tight control. This study aimed to investigate the association between calcium-magnesium ratio in hair and subclinical coronary artery calcification. Using multiple linear regression analysis, we examined the associations between calcium-magnesium ratio in hair and the coronary calcium score (CCS) in 216 Koreans aged 40 years and above (122 men and 94 women). We found that the calcium-to-magnesium ratio in hair was independently and positively associated with CCS after adjusting for age and sex (regression coefficient 6.051 ± 2.329, P = 0.010). When we assessed the association between the calcium-magnesium ratio and CCS after adjusting for potential cardiovascular risk factors and vascular function modifying drugs, we found that the strength of association with CCS was comparable to before (regression coefficient 5.434 ± 2.523, P = 0.032). Our findings suggest that among middle-aged and elderly Koreans without clinical CVD, the association between coronary artery calcification and hair calcium-magnesium ratio is stronger in those with a higher calcium-magnesium ratio in hair than in those with a lower ratio.

Magnesium Counteracts Vascular Calcification: Passive Interference or Active Modulation?

Over the last decade, an increasing number of studies report a close relationship between serum magnesium concentration and cardiovascular disease risk in the general population. In end-stage renal disease, an association was found between serum magnesium and survival. Hypomagnesemia was identified as a strong predictor for cardiovascular disease in these patients. A substantial body of in vitro and in vivo studies has identified a protective role for magnesium in vascular calcification. However, the precise mechanisms and its contribution to cardiovascular protection remain unclear. There are currently 2 leading hypotheses: first, magnesium may bind phosphate and delay calcium phosphate crystal growth in the circulation, thereby passively interfering with calcium phosphate deposition in the vessel wall. Second, magnesium may regulate vascular smooth muscle cell transdifferentiation toward an osteogenic phenotype by active cellular modulation of factors associated with calcification. Here, the data supporting these major hypotheses are reviewed. The literature supports both a passive inorganic phosphate-buffering role reducing hydroxyapatite formation and an active cell-mediated role, directly targeting vascular smooth muscle transdifferentiation. However, current evidence relies on basic experimental designs that are often insufficient to delineate the underlying mechanisms. The field requires more advanced experimental design, including determination of intracellular magnesium concentrations and the identification of the molecular players that regulate magnesium concentrations in vascular smooth muscle cells.

Determinants of hypomagnesemia in patients with type 2 diabetes mellitus

BACKGROUND

Hypomagnesemia (plasma magnesium (Mg²⁺) concentration <0.7 mmol/L) has been described in patients with type 2 diabetes. Polypharmacy is inevitable when treating a complex disease such as type 2 diabetes and could explain disturbances in the plasma Mg²⁺ concentration. In this study, we aimed to establish the extent of hypomagnesemia in a cohort of type 2 diabetes patients and to identify the determinants of plasma Mg²⁺ levels.

METHODS

Patient data and samples of 395 type 2 diabetes patients were investigated. Plasma Mg²⁺ concentrations were measured using a spectrophotometric assay. Using Pearson correlation analyses, variables were correlated to plasma Mg²⁺ levels. After excluding confounding variables, all parameters correlating (P < 0.1) with plasma Mg²⁺ were included in a stepwise backward regression model.

RESULTS

The mean plasma Mg²⁺ concentration in this cohort was 0.74 ± 0.10 mmol/L. In total, 121 patients (30.6%) suffered from hypomagnesemia. Both plasma triglyceride (r = -0.273, P < 0.001) and actual glucose levels (r = -0.231, P < 0.001) negatively correlated with the plasma Mg²⁺ concentration. Patients using metformin (n = 251, 62%), proton pump inhibitors (n = 179, 45%) or β-adrenergic receptor agonists (n = 31, 8%) displayed reduced plasma Mg²⁺ levels. Insulin use (n = 299, 76%) positively correlated with plasma Mg²⁺ levels. The model predicted (R²) 20% of all variance in the plasma Mg²⁺ concentration.

CONCLUSIONS

Hypomagnesemia is highly prevalent in type 2 diabetes patients. Plasma triglycerides and glucose levels are major determinants of the plasma Mg²⁺ concentration, whereas only a minor part (<10%) of hypomagnesemia can be explained by drug intake, excluding polypharmacy as a major cause for hypomagnesemia in type 2 diabetes.

The association of serum magnesium and mortality outcomes in heart failure patients: A systematic review and meta-analysis

BACKGROUND

Low serum magnesium (Mg) has been independently shown to increase risk of heart failure (HF), but data on the association between serum Mg concentration and the outcome of patients with HF are conflicting. The purpose of this systematic review and meta-analysis was to estimate the prognostic effects of hypermagnesemia and hypomagnesemia on cardiovascular (CV) mortality and all-cause mortality (ACM) of patients with HF.

METHODS

Relevant studies were identified from Medline and Scopus databases. Included and excluded criteria were defined. Effects (i.e., log [risk ratio [RR]]) of hypomagnesemia and hypermagnesemia versus normomagnesemia were estimated using Poisson regression, and then a multivariate meta-analysis was applied for pooling RRs across studies. Heterogeneity was explored using a meta-regression and subgroup analysis.

RESULTS

On analysis, 7 eligible prospective studies yielded a total of 5172 chronic HF patients with 913 and 1438 deaths from CV and ACM, respectively. Most participants were elderly men with left ventricular (LV) ejection fraction ≤40%. Those patients with baseline hypermagnesemia had a significantly higher risk of CV mortality (RR, 1.38; 95% confidence interval [CI], 1.07-1.78) or ACM (RR, 1.35; 95% CI, 1.18-1.54) than those with baseline normomagnesemia. However, baseline hypomagnesemia was not associated with the risk of CV mortality (RR, 1.11; 95% CI, 0.79-1.57) and ACM (RR, 1.11; 95% CI, 0.87-1.41). A subgroup analysis by Mg cutoff suggested a dose-response trend for hypermagnesemia effects, that is, the pooled RRs for CV mortality were 1.28 (95% CI, 1.05-1.55) and 1.92 (95% CI, 1.00-3.68) for the cutoff of 0.89 to 1.00 and 1.05 to 1.70 mmol/L, respectively.

CONCLUSION

The present systematic review and meta-analysis suggested that, in HF patients, hypermagnesemia with serum Mg ≥ 1.05 mmol/L was associated with an increased risk of CV mortality and ACM but this was not observed for hypomagnesemia. This finding was limited to the elderly patients with chronic HF who had reduced LV systolic function.

Why are serum magnesium levels lower in Saudi dialysis patients?

Objectives

Serum magnesium (Mg) levels are often altered in dialysis patients. This study was conducted to ascertain the trends in Mg levels in patients on dialysis treatment.

Methods

A retrospective study was performed in the Dialysis Unit of King Khalid University Hospital, King Saud University, Riyadh, on patients undergoing regular dialysis. Patient demographic data, including body mass index (BMI), serum calcium (Ca), Mg, parathyroid hormone (PTH), cholesterol, and triglycerides were documented.

Results

Of a total of 115 patients, 70 (60.9%) were on haemodialysis (HD), and 45 (39.1%) were on peritoneal dialysis (PD). Of these, 10 patients (8.7%) had Mg levels of <0.7 mmol/L, 13 (11.3%) had 0.7 mmol/L, 24 (20.9%) had 0.8 mmol/L, 26 (22.6%) had 0.9 mmol/L, 16 (13.9%) 1.0 mmol/L, and 26 (23.9%) showed levels of ≥1.1 mmol/L. Approximately 93.0% had increased PTH levels, 43 (37.4%) had decreased serum Ca, 24 (20.9%) had low serum cholesterol, and 60 (52.2%) had low serum triglyceride. PD patients had significantly lower Mg and higher PTH levels compared to HD patients.

Conclusion

Patients with chronic kidney disease are generally considered at risk of developing hypermagnesaemia due to reduced renal excretion. However, a considerable number of dialysis patients in our unit had hypomagnesaemia (or low levels) instead. In addition to other factors, PTH secretion is affected by serum Mg levels. We found a significant correlation between serum Mg and Ca as well as PTH levels. Consequently, optimizing Mg concentration in patients on dialysate is essential to reduce risk of dyslipidaemia, arrhythmias, hyperparathyroidism, or adynamic bone disease.

Magnesium Attenuates Phosphate-Induced Deregulation of a MicroRNA Signature and Prevents Modulation of Smad1 and Osterix during the Course of Vascular Calcification

Vascular calcification (VC) is prevalent in patients suffering from chronic kidney disease (CKD). High phosphate levels promote VC by inducing abnormalities in mineral and bone metabolism. Previously, we demonstrated that magnesium (Mg(2+)) prevents inorganic phosphate- (Pi-) induced VC in human aortic vascular smooth muscle cells (HAVSMC). As microRNAs (miR) modulate gene expression, we investigated the role of miR-29b, -30b, -125b, -133a, -143, and -204 in the protective effect of Mg(2+) on VC. HAVSMC were cultured in the presence of 3 mM Pi with or without 2 mM Mg(2+) chloride. Total RNA was extracted after 4 h, 24 h, day 3, day 7, and day 10. miR-30b, -133a, and -143 were downregulated during the time course of Pi-induced VC, whereas the addition of Mg(2+) restored (miR-30b) or improved (miR-133a, miR-143) their expression. The expression of specific targets Smad1 and Osterix was significantly increased in the presence of Pi and restored by coincubation with Mg(2+). As miR-30b, miR-133a, and miR-143 are negatively regulated by Pi and restored by Mg(2+) with a congruent modulation of their known targets Runx2, Smad1, and Osterix, our results provide a potential mechanistic explanation of the observed upregulation of these master switches of osteogenesis during the course of VC.

MICS, an easily ignored contributor to arterial calcification in CKD patients

In chronic kidney disease (CKD), simultaneous mineral and skeleton changes are prevalent, known as CKD-mineral bone disorder (CKD-MBD). Arterial calcification (AC) is a clinically important complication of CKD-MBD. It can increase arterial stiffness, which leads to severe cardiovascular events. However, current treatments have little effect on regression of AC, as its mechanisms are still unclear. There are multiple risk factors of AC, among which Malnutrition-Inflammation Complex Syndrome (MICS) is a new and crucial one. MICS, a combined syndrome of malnutrition and inflammation, generally begins at the early stage of CKD and becomes obvious in end-stage renal disease (ESRD). It was linked to reverse epidemiology and associated with increased cardiovascular mortality in ESRD patients. Recent data suggest that MICS can trigger CKD-MBD and accelerate the course of AC. In this present review, we summarize the recent understanding about the aggravating effects of MICS on AC and discuss the possible underlying mechanisms. A series of findings indicate that targeting MICS will provide a potential strategy for treating AC in CKD.

Hypomagnesemia as a predictor of mortality in hemodialysis patients and the role of proton pump inhibitors: A cross-sectional, 1-year, retrospective cohort study

Introduction This study aimed to evaluate the association between proton pump inhibitor (PPI) use and serum magnesium levels, and the role of hypomagnesemia and PPI use as a risk factor for mortality in hemodialysis patients. Methods An observational study, including a cross-sectional and 1-year retrospective cohort study. The study comprised 399 hemodialysis patients at a single center, and was conducted from January to September 2014. Multiple linear regression analysis was used to investigate the independent relationship between serum magnesium levels and baseline demographic and clinical variables, including PPI and histamine-2 receptor antagonist use. Cox regression model was used to identify lower serum magnesium level and PPI as a predictor of 1-year mortality. Findings Serum magnesium levels were lower with PPI use than non-PPI use (2.39 ± 0.36 vs. 2.56 ± 0.39 mg/dL, P < 0.001). Multiple linear regression analysis showed that PPI use, low serum albumin levels, and low serum potassium and high-sensitivity C-reactive protein (hs-CRP) levels were significantly associated with low serum magnesium levels. A total of 29 deaths occurred during the follow-up period. According to Cox regression analysis stratified by hs-CRP, only high serum hs-CRP levels (>4.04 mg/L) in association with low serum magnesium levels was an independent risk factor for 1-year mortality (hazard ratio: 2.92; 95% CI: 1.53-6.40, P < 0.001). Discussion Serum magnesium levels are lower in PPI use. In the inflammatory state, a low serum magnesium level is a significant predictor of mortality in hemodialysis patients.