Recommendation on an updated standardization of serum magnesium reference ranges

A Comprehensive Review on Understanding Magnesium Disorders: Pathophysiology, Clinical Manifestations, and Management Strategies

Magnesium is vital in a broad spectrum of physiological processes, including enzyme activity, energy production, and neuromuscular function. Despite its crucial role, magnesium disorders - comprising both deficiency (hypomagnesemia) and excess (hypermagnesemia) - are frequently underrecognized and inadequately managed in clinical practice. Magnesium deficiency is widespread, particularly among populations with chronic illnesses, the elderly, and those experiencing malnutrition, often leading to significant neuromuscular, cardiovascular, and metabolic complications. Conversely, hypermagnesemia, though less common, poses serious risks, especially in individuals with impaired renal function or those receiving high doses of magnesium supplements or medications. This review comprehensively examines magnesium disorders, detailing their pathophysiology, clinical manifestations, and management strategies. It highlights the essential functions of magnesium in maintaining cellular integrity, cardiovascular health, and bone structure and discusses the global prevalence and risk factors associated with magnesium imbalances. By offering insights into the current understanding of magnesium homeostasis and its disruptions, this review aims to enhance the awareness and treatment of magnesium-related conditions, ultimately improving patient outcomes across diverse clinical settings.

Brain of miyoshi myopathy/dysferlinopathy patients presents with structural and metabolic anomalies

Miyoshi myopathy/dysferlinopathy (MMD) is a rare muscle disease caused by DYSF gene mutations. Apart from skeletal muscles, DYSF is also expressed in the brain. However, the impact of MMD-causing DYSF variants on brain structure and function remains unexplored. To investigate this, we utilized magnetic resonance (MR) modalities (MR volumetry and 31P MR spectroscopy) in a family with seven children, four of whom have the illness. The MMD siblings showed distinct differences from healthy controls: (1) a significant (p < 0.001) right-sided volume asymmetry (+ 232 mm3) of the inferior lateral ventricles; and (2) a significant (p < 0.001) decrease in [Mg2+], along with a modified energy metabolism profile and altered membrane turnover in the hippocampus and motor and premotor cortices. The patients' [Mg2+], energy metabolism, and membrane turnover measures returned to those of healthy relatives after a month of 400 mg/day magnesium supplementation. This work is the first to describe anatomical and functional abnormalities characteristic of neurodegeneration in the MMD brain. Therefore, we call for further examination of brain functions in larger cohorts of MMD patients and testing of magnesium supplementation, which has proven to be an effective corrective approach in our study.

The Role of Magnesium in Parkinson's Disease: Status Quo and Implications for Future Research

Neurodegenerative diseases represent an increasing economic, social, and, above all, medical burden worldwide. The second most prevalent disease in this category is Parkinson's disease, surpassed only by Alzheimer's. It is a treatable but still incurable systemic disease with a pathogenesis that has not yet been elucidated. Several theories are currently being developed to explain the causes and progression of Parkinson's disease. Magnesium is one of the essential macronutrients and is absolutely necessary for life as we know it. The magnesium cation performs several important functions in the cell in the context of energetic metabolism, substrate metabolism, cell signalling, and the regulation of the homeostasis of other ions. Several of these cellular processes have been simultaneously described as being disrupted in the development and progression of Parkinson's disease. The relationship between magnesium homeostasis and the pathogenesis of Parkinson's disease has received little scientific attention to date. The aim of this review is to summarise and critically evaluate the current state of knowledge on the possible role of magnesium in the pathogenesis of Parkinson's disease and to outline possible future directions for research in this area.

Association between magnesium depletion score and chronic obstructive pulmonary disease risk: a secondary data analysis from NHANES

BACKGROUND AND OBJECTIVE

The association between magnesium depletion score (MDS) and the risk of chronic obstructive pulmonary disease (COPD) has not been examined to date. Meanwhile, the potential impact of dietary magnesium intake on this association remains unclear. This study aimed to investigate the influence of dietary magnesium intake on the association between MDS and COPD incidence.

METHODS

In this cross-sectional study using the National Health and Nutrition Examination Survey database, we analysed the relationship between MDS and COPD, while also exploring the role of dietary magnesium.

RESULTS

A total of 39 852 participants, including 1762 patients with COPD and 38 090 patients with non-COPD, were included in the analysis. After adjusting for confounding factors, our results demonstrated a significant association between higher MDS and increased COPD incidence (OR=1.48, 95% CI: 1.10 to 1.99). Furthermore, it was observed that dietary magnesium intake did not significantly impact this association.

CONCLUSION

This study highlights a significant positive correlation between MDS and the incidence of COPD. Nonetheless, no significant alteration in this association was observed with dietary magnesium intake.

Association between Serum Magnesium Levels and Risk of Dyslipidemia: A Cross-Sectional Study from the China Health and Nutrition Survey

A growing number of observational studies have been carried out on the relationship between serum magnesium and risk of dyslipidemia, but their results were conflicting. This study aimed to investigate the association between serum magnesium levels and risk of dyslipidemia in Chinese adult residents. We used data from the China Health and Nutrition Survey (CHNS) in the wave of 2009 to conduct a cross-sectional study. A total of 8,457 participants (47.2% male) with a mean age of 50.5 years were assessed and divided into 4 groups based on quartiles of serum magnesium levels. We found that higher quartiles of serum magnesium were associated with increased prevalence of dyslipidemia. After adjustment for confounders, the results of logistic regression analyses indicated that there was an increased trend in dyslipidemia risk as quartiles of serum magnesium increased. The restricted cubic spline model revealed a nonlinear relationship between serum magnesium levels and dyslipidemia. In subgroup analyses, the positive relationship between serum magnesium levels and dyslipidemia was more significant in females than in males. Our study suggested that serum magnesium levels were positively associated with risk of dyslipidemia in Chinese adult population. Further research is needed to provide a deep understanding of the underlying mechanism of magnesium on lipid metabolism.

Serum Magnesium Levels in Patients with Chronic Kidney Disease: Is There a Relationship with Inflammation Status?

BACKGROUND

Magnesium (Mg2+) is a fundamental mineral that maintains cellular function, and low levels may be linked to inflammation in patients with chronic kidney disease (CKD). This cross-sectional study evaluated the correlation between serum Mg2+ levels and the inflammatory status in patients undergoing dialysis.

METHODS

Two hundred patients with CKD [150 undergoing hemodialysis (HD), 50 (18) years; BMI 24 (4.8) kg/m²; and 50 patients on peritoneal dialysis (PD), 54 (17.7) years; BMI, 27.5 (7.3) kg/m²] were included. Serum Mg2+ levels were evaluated using a colourimetric test and commercial kit. Inflammatory markers were assessed by ELISA and multiplex bead-based assay. Lipid peroxidation was evaluated using thiobarbituric acid-reactive substances.

RESULTS

The median serum Mg2+ levels were 2.3 (0.5) mg/dL, and 21% of patients presented Mg2+ deficiency (< 2.07 mg/dL or 0.85 mmol/L). We found no difference in Mg2+ serum levels between the two groups. A significant negative correlation was observed between serum Mg2+ levels and plasma hs-CRP (r =-0.17, p = 0.01), IL-8 (r =-0.35, p = 0.01), and MCP-1 (r =-0.31, p = 0.03) levels.

CONCLUSION

Mg2+ serum levels were negatively correlated with inflammatory status in patients with CKD on dialysis.

Dexmedetomidine and magnesium sulfate in preventing junctional ectopic tachycardia after pediatric cardiac surgery

BACKGROUND

Junctional ectopic tachycardia (JET) is a serious tachyarrhythmia following pediatric cardiac surgery. It isn't easy to treat and better to be prevented. This study aimed to examine the prophylactic effects of dexmedetomidine, MgSO4, or their combination in reducing JET following pediatric open cardiac surgery.

METHODS

Hundred and twenty children under 5 years, weighing more than 5 kg, who were scheduled for corrective acyanotic cardiac surgeries were randomized into three groups. Group MD (Dexmedetomidine-MgSO4 group): received dexmedetomidine 0.5 μg/kg IV over 20 min after induction, then infusion 0.5 μg/kg/h for 72 h, and 50 mg/kg bolus of MgSO4 with aortic cross-clamp release, then continued administration for 72 h postoperatively at a dose of 30 mg/kg/day. Group D (the dexmedetomidine group) received the same dexmedetomidine as the MD group in addition to normal saline instead of MgSO4. Group C (control group): received normal saline instead of dexmedetomidine and MgSO4. The primary outcome was the detection of JET incidence; the secondary outcomes were hemodynamic parameters, ionized Mg, vasoactive-inotropic score, extubation time, PCCU and hospital stay, and perioperative complications.

RESULTS

The incidence of JET was significantly reduced in Group MD and Group D (p = .007) compared to Group C. Ionized Mg was significantly higher in Group MD than in Groups D and C during rewarming and in the ICU (p < .001). Better hemodynamic profile in Group MD compared to Group D and Group C throughout surgery and in the ICU, the predictive indexes were significantly better in Group MD than in Groups D and C (p < .001). Including the extubation time, PCCU, and hospital stay.

CONCLUSION

Dexmedetomidine alone or combined with MgSO4 had a therapeutic role in the prevention of JET in children after congenital heart surgery.

Electrocardiogram Features in Non-Cardiac Diseases: From Mechanisms to Practical Aspects

Despite the noteworthy advancements and the introduction of new technologies in diagnostic tools for cardiovascular disorders, the electrocardiogram (ECG) remains a reliable, easily accessible, and affordable tool to use. In addition to its crucial role in cardiac emergencies, ECG can be considered a very useful ancillary tool for the diagnosis of many non-cardiac diseases as well. In this narrative review, we aimed to explore the potential contributions of ECG for the diagnosis of non-cardiac diseases such as stroke, migraine, pancreatitis, Kounis syndrome, hypothermia, esophageal disorders, pulmonary embolism, pulmonary diseases, electrolyte disturbances, anemia, coronavirus disease 2019, different intoxications and pregnancy.

Magnesium in hypertension: mechanisms and clinical implications

Hypertension is associated with increased risk of cardiovascular disease and death. Evidence suggests that Mg2+ depletion contributes to hypertension. It is estimated that 25% or more of the United States population experiences chronic, latent Mg2+ depletion. This review explores mechanisms by which Mg2+ influences blood pressure, modifying risk of hypertension and complicating its treatment. Mechanisms addressed include effects upon i) sympathetic tone, via the modulation of N-methyl-D-aspartate (NMDA) receptor and N-type Ca2+ channel activity, influencing catecholamine release from sympathetic nerve endings; ii) vascular tone, via alteration of L-type Ca2+ and endothelial nitric oxide synthase (eNOS) activity and prostacyclin release; iii) renal K+ handling, influencing systemic K+ balance and potentially indirectly influencing blood pressure; iv) aldosterone secretion from the adrenal cortex; and v) modulation of pro-hypertensive inflammatory processes in dendritic cells and macrophages, including activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome and stimulation of isolevuglandin (IsoLG) production. Discovery of these mechanisms has furthered our understanding of the pathogenesis of hypertension, with implications for treatment and has highlighted the role of Mg2+ balance in hypertension and cardiovascular disease.

Association between circulating micronutrient pattern, glycemic control, and insulin resistance in type 2 diabetes mellitus

The circulating micronutrient pattern in type 2 diabetes mellitus (T2DM) may impact glycemic control and insulin resistance; however, there is a scarcity of studies that have evaluated the circulating micronutrient pattern in the T2DM population. Therefore, our objective was to identify circulating micronutrient pattern and their association with markers of glycemic control and insulin resistance in individuals with T2DM. We developed a cross-sectional observational study involving adults with T2DM in Sergipe, Brazil. We assessed plasma levels of magnesium, zinc, calcium, potassium, and serum 25-hydroxyvitamin D. Additionally, also measured fasting glucose levels, the percentage of glycated hemoglobin (%HbA1c), and calculated the homeostatic model assessment for insulin resistance (HOMA-IR). Patterns of body reserve were established using principal component analysis and categorized into quartiles. Binary logistic regression models were employed. We evaluated 114 individuals (63.7% women), with a median age and body mass index of 49 years and 29.6 kg/m², respectively. Two circulating micronutrient patterns were identified, explaining 62.5% of the variance: Pattern 1 (positive contributions from magnesium, zinc, calcium, and potassium) and Pattern 2 (positive contributions from 25-hydroxyvitamin D and zinc, with a negative contribution from potassium). Lowest quartile for Pattern 1 and Pattern 2 exhibiting a 4.32-fold (p = 0.019) and 3.97-fold (p = 0.038) higher likelihood of increasing HOMA-IR and %HbA1c values, respectively, compared to the larger quartiles. However, no associations were found between these patterns and fasting glucose values. Lowest quartile for both patterns of micronutrients was associated with inadequate metabolic control in individuals with T2DM.

Association and dose-response relationship of plasma magnesium with metabolic syndrome in Chinese adults older than 45 years

Purpose

Magnesium (Mg) is an essential nutrient for the maintenance of vital physiological functions. Magnesium deficiency is associated with diseases such as obesity, type 2 diabetes mellitus (T2DM), and metabolic syndrome (MetS); however, conclusions have been inconsistent, and there is a particular lack of evidence regarding this association in Chinese population older than 45 years. This study aimed to assess the association between plasma magnesium and the risk of MetS and its components, the dose-response relationship, and the threshold effect relationship in a Chinese population involving older than 45 years.

Methods

A total of 2,101 individuals were randomly selected from the China Nutrition and Health Surveillance (CNHS) (2015-2017) by considering monitoring points. We used the joint statement of the International Diabetes Federation (IDF) in 2009 to define participants with MetS. The plasma magnesium was tested by inductively coupled plasma mass spectrometry (ICP-MS). The logistic regression and restricted cubic spline (RCS) models were used to analyze the association and dose-response relationship between plasma Mg and MetS and its components.

Results

Compared with the lowest quintile (Q1) for plasma Mg, the odds ratios (ORs) and 95% confidence intervals (95% CI) for MetS, impaired fasting glucose (IFG), hypertension, and triglyceride (TG) elevation at the highest quintile (Q5) were 0.419 (0.301, 0.583), 0.303 (0.221, 0.415), 0.446 (0.322, 0.618), and 0.526 (0.384, 0.720), respectively, with all p < 0.05. However, in the components of decreased high-density lipoprotein cholesterol (HDL-C) and central obesity, no trend toward lowering with higher plasma magnesium was observed (p = 0.717, p = 0.865). These associations were not altered by further adjustment for potential confounding variables, including age, gender, education, nationality, area, residence, body mass index (BMI), and heart rate. The RCS analysis showed that, when plasma magnesium was lower than 0.85 mmol/L, the curve was leveled off, and then, the curve showed a decreasing trend with the increase in plasma magnesium.

Conclusion

Therefore, plasma Mg was negatively associated with MetS and its components (including IFG, hypertension, and elevated TG) in people older than 45 years. In addition, plasma Mg greater than or equal to 0.85 mmol/L, which is higher than the commonly used threshold of 0.75 mmol/L, may be protective against MetS and its components (including elevated FPG, elevated blood pressure, and elevated TG). More prospective studies, such as randomized controlled trials, are necessary to confirm the effective impact of Mg on MetS and its components. Plasma Mg levels in the MetS population older than 45 years require attention.

Serum Magnesium Is Associated with Long-Term Survival of Non-ST-Elevation Myocardial Infarction Patients

BACKGROUND

Low serum magnesium (sMg) is associated with cardiovascular risk factors and atherosclerotic disease.

OBJECTIVE

To evaluate the association between sMg levels on admission and clinical outcomes in hospitalized non-ST-elevation myocardial infarction (NSTEMI) patients.

METHODS

A retrospective analysis of all patients admitted to a single tertiary center with a primary diagnosis of NSTEMI. Patients with advanced chronic kidney disease were excluded. Clinical data were collected and compared between lower sMg quartile patients (Q1; sMg < 1.9 mg/dL) and all other patients (Q2-Q4; sMg ≥ 1.9 mg/dL).

RESULTS

The study cohort included 4552 patients (70% male, median age 69 [IQR 59-79]) who were followed for a median of 4.4 (IQR 2.4-6.6) years. The median sMg level in the low sMg group was 1.7 (1.6-1.8) and 2.0 (2.0-2.2) mg/dL in the normal/high sMg group. The low sMg group was older (mean of 72 vs. 67 years), less likely to be male (64% vs. 72%), and had higher rates of comorbidities, including diabetes, hypertension, and atrial fibrillation (59% vs. 29%, 92% vs. 85%, and 6% vs. 5%; p < 0.05 for all). Kaplan-Meier survival analysis demonstrated significantly higher cumulative death probability at 4 years in the low sMg group (34% vs. 22%; p log rank <0.001). In a multivariable analysis model adjusted for sex, significant comorbidities, coronary interventions during the hospitalization, and renal function, the low sMg group exhibited an independent 24% increased risk of death during follow up (95% CI 1.11-1.39; p < 0.001).

CONCLUSIONS

Low sMg is independently associated with higher risk of long-term mortality among patients recovering from an NSTEMI event.

Gene-nutrient interactions that impact magnesium homeostasis increase risk for neural tube defects in mice exposed to dolutegravir

In 2018, data from a surveillance study in Botswana evaluating adverse birth outcomes raised concerns that women on antiretroviral therapy (ART) containing dolutegravir (DTG) may be at increased risk for neural tube defects (NTDs). The mechanism of action for DTG involves chelation of Mg2+ ions in the active site of the viral integrase. Plasma Mg2+ homeostasis is maintained primarily through dietary intake and reabsorption in the kidneys. Inadequate dietary Mg2+ intake over several months results in slow depletion of plasma Mg2+ and chronic latent hypomagnesemia, a condition prevalent in women of reproductive age worldwide. Mg2+ is critical for normal embryonic development and neural tube closure. We hypothesized that DTG therapy might slowly deplete plasma Mg2+ and reduce the amount available to the embryo, and that mice with pre-existing hypomagnesemia due to genetic variation and/or dietary Mg2+ insufficiency at the time of conception and initiation of DTG treatment would be at increased risk for NTDs. We used two different approaches to test our hypothesis: 1) we selected mouse strains that had inherently different basal plasma Mg2+ levels and 2) placed mice on diets with different concentrations of Mg2+. Plasma and urine Mg2+ were determined prior to timed mating. Pregnant mice were treated daily with vehicle or DTG beginning on the day of conception and embryos examined for NTDs on gestational day 9.5. Plasma DTG was measured for pharmacokinetic analysis. Our results demonstrate that hypomagnesemia prior to conception, due to genetic variation and/or insufficient dietary Mg2+ intake, increases the risk for NTDs in mice exposed to DTG. We also analyzed whole-exome sequencing data from inbred mouse strains and identified 9 predicted deleterious missense variants in Fam111a that were unique to the LM/Bc strain. Human FAM111A variants are associated with hypomagnesemia and renal Mg2+ wasting. The LM/Bc strain exhibits this same phenotype and was the strain most susceptible to DTG-NTDs. Our results suggest that monitoring plasma Mg2+ levels in patients on ART regimens that include DTG, identifying other risk factors that impact Mg2+ homeostasis, and correcting deficiencies in this micronutrient might provide an effective strategy for mitigating NTD risk.

Serum Magnesium Levels and Cardiovascular Outcomes in Systolic Blood Pressure Intervention Trial Participants

Rationale and Objective

Serum magnesium levels have been inversely yet inconsistently associated with cardiovascular (CV) outcomes. In this study, we examined the association of serum magnesium levels with CV outcomes in the Systolic Blood Pressure Intervention Trial (SPRINT) participants.

Study Design

Case-control post hoc analysis of SPRINT.

Setting & Participants

A total of 2,040 SPRINT participants with available serum samples at baseline level were included in this study. Case participants (n = 510) who experienced a CV event during the SPRINT observation period (median follow-up of 3.2 years) and control participants (n = 1,530) without CV events were sampled in a 1:3 ratio for measurements of serum magnesium level at baseline and 2-year follow-up.

Predictors

Baseline serum magnesium levels and 2-year percentage change in serum magnesium levels (ΔSMg).

Outcome

SPRINT primary composite CV outcome.

Analytical Approach

Multivariable conditional logistic regression analysis, accounting for matching factors, was used to evaluate the association of baseline and ΔSMg with CV outcomes. Individual matching of cases and controls was based on the SPRINT treatment arm allocation (standard vs intensive) and prevalence of chronic kidney disease (CKD).

Results

The median serum magnesium level at baseline was similar among the case and control groups. In a fully adjusted model, each standard deviation (SD) (0.18 mg/dL) higher of the baseline serum magnesium level was independently associated with a lower risk for composite CV outcomes in all study participants (adjusted odds ratio 95% CI, 0.79 [0.70-0.89]). This association was similar when serum magnesium levels were analyzed in quartiles but dissipated in the standard (vs intensive) arm of SPRINT (0.88 [0.76-1.02] vs 0.65 [0.53-0.79], respectively; Pinteraction = 0.06). The presence or absence of CKD at baseline did not modify this association. ΔSMg was not independently associated with CV outcomes occurring after 2 years.

Limitations

ΔSMg was small in magnitude, limiting effect size.

Conclusions

Higher baseline serum magnesium levels were independently associated with reduced risk for CV outcomes in all study participants, but ΔSMg was not associated with CV outcomes.

Importance of Magnesium Status in COVID-19

A large amount of published research points to the interesting concept (hypothesis) that magnesium (Mg) status may have relevance for the outcome of COVID-19 and that Mg could be protective during the COVID disease course. As an essential element, Mg plays basic biochemical, cellular, and physiological roles required for cardiovascular, immunological, respiratory, and neurological functions. Both low serum and dietary Mg have been associated with the severity of COVID-19 outcomes, including mortality; both are also associated with COVID-19 risk factors such as older age, obesity, type 2 diabetes, kidney disease, cardiovascular disease, hypertension, and asthma. In addition, populations with high rates of COVID-19 mortality and hospitalization tend to consume diets high in modern processed foods, which are generally low in Mg. In this review, we review the research to describe and consider the possible impact of Mg and Mg status on COVID-19 showing that (1) serum Mg between 2.19 and 2.26 mg/dL and dietary Mg intakes > 329 mg/day could be protective during the disease course and (2) inhaled Mg may improve oxygenation of hypoxic COVID-19 patients. In spite of such promise, oral Mg for COVID-19 has thus far been studied only in combination with other nutrients. Mg deficiency is involved in the occurrence and aggravation of neuropsychiatric complications of COVID-19, including memory loss, cognition, loss of taste and smell, ataxia, confusion, dizziness, and headache. Potential of zinc and/or Mg as useful for increasing drug therapy effectiveness or reducing adverse effect of anti-COVID-19 drugs is reviewed. Oral Mg trials of patients with COVID-19 are warranted.

Magnesium Deficiency and Cardiometabolic Disease

Magnesium (Mg²⁺) has many physiological functions within the body. These include important roles in maintaining cardiovascular functioning, where it contributes to the regulation of cardiac excitation-contraction coupling, endothelial functioning and haemostasis. The haemostatic roles of Mg²⁺ impact upon both the protein and cellular arms of coagulation. In this review, we examine how Mg²⁺ homeostasis is maintained within the body and highlight the various molecular roles attributed to Mg²⁺ in the cardiovascular system. In addition, we describe how nutritional and/or disease-associated magnesium deficiency, seen in some metabolic conditions, has the potential to influence cardiac and vascular outcomes. Finally, we also examine the potential for magnesium supplements to be employed in the prevention and treatment of cardiovascular disorders and in the management of cardiometabolic health.

Admission Serum Magnesium Levels Is Associated with Short and Long-Term Clinical Outcomes in COVID-19 Patients

BACKGROUND

In the face of the global pandemic that the coronavirus disease 2019 (COVID-19) has created, readily available prognostic markers may be of great use.

OBJECTIVE

To evaluate the association between serum magnesium (sMg) levels on admission and clinical outcomes in hospitalized COVID-19 patients.

METHODS

We retrospectively analyzed all patients admitted to a single tertiary center with a primary de novo diagnosis of COVID-19. Patients were followed for a mean of 10 ± 7 months. Demographic, clinical and laboratory data were collected and compared between five groups of patients according to sMg quintiles on hospital admission.

RESULTS

The cohort included 1522 patients (58% male, 69 ± 17 years old). A low sMg level (1st quintile) was associated with higher rates of diabetes and steroid use, whereas a high sMg level (5th quintile) was associated with dyslipidemia, renal dysfunction, higher levels of inflammatory markers and stay in the intensive care unit. All-cause in-hospital and long-term mortality was higher in patients with both low and high sMg levels, compared with mid-range sMg levels (2nd, 3rd and 4th quintiles; 19% and 30% vs. 9.5%, 10.7% and 17.8% and 35% and 45.3% vs. 23%, 26.8% and 27.3% respectively; p < 0.001 for all). After adjusting for significant clinical parameters indicating severe disease and renal dysfunction, only low sMg state was independently associated with increased mortality (HR = 1.57, p < 0.001).

CONCLUSIONS

Both low and high sMg levels were associated with increased mortality in a large cohort of hospitalized COVID-19 patients. However, after correction for renal dysfunction and disease severity, only low sMg maintained its prognostic ability.

The association of serum magnesium with infection in new-onset systemic lupus erythematosus patients

OBJECTIVE

To assess the association of serum magnesium with infection in new-onset systemic lupus erythematosus (SLE) patients.

METHODS

We conducted a single-center retrospective cohort study of new-onset SLE patients from 2012 to 2021. The hospitalized SLE patients were divided into infection and noninfection groups. Logistic regression analysis was conducted to examine the association of hypomagnesemia with infection.

RESULTS

A total of 476 new-onset SLE patients were included, with 299 cases in the infection group and 177 cases in the noninfection group. The patients were mostly females (81.7%). The average age at diagnosis was 43.7 years. The median duration was 1.0 month. The prevalence of hypomagnesemia (<0.70), normomagnesemia (0.70-1.10), and hypermagnesemia (>1.10) in new-onset SLE patients was 14.3%, 83.4%, and 2.3%, respectively. The prevalence of hypomagnesemia was 18.4% in the infection group and 7.3% in the noninfection group (p = .001). The baseline value of serum magnesium was 0.819 mmol/L, with values of 0.799 mmol/L in the infection group and 0.854 mmol/L in the noninfection group (p = .000). The following clinical variables were significantly different between the two groups (p < .05): age, duration, hospitalization stay, fever, serositis, and SLE Disease Activity Index 2000 (SLEDAI 2K). The laboratory parameters, including hemoglobin, white blood cell count, albumin level, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), procalcitonin, and complement C3 were also significantly different between the two groups (p < .05). The mortality was 4.4% (21/476), with 20 cases occurring in the infection group. Logistic regression analysis showed that hypomagnesemia was associated with an increased risk of infection (p = .001) and poor prognosis (p = .015).

CONCLUSION

Hypermagnesemia was rare in new-onset SLE patients. Hypomagnesemia was common and was associated with an increased risk of infection in new-onset SLE patients.

Magnesium reabsorption in the kidney

Mg²⁺ is essential for many cellular and physiological processes, including muscle contraction, neuronal activity, and metabolism. Consequently, the blood Mg²⁺ concentration is tightly regulated by balanced intestinal Mg²⁺ absorption, renal Mg²⁺ excretion, and Mg²⁺ storage in bone and soft tissues. In recent years, the development of novel transgenic animal models and identification of Mendelian disorders has advanced our current insight in the molecular mechanisms of Mg²⁺ reabsorption in the kidney. In the proximal tubule, Mg²⁺ reabsorption is dependent on paracellular permeability by claudin-2/12. In the thick ascending limb of Henle's loop, the claudin-16/19 complex provides a cation-selective pore for paracellular Mg²⁺ reabsorption. The paracellular Mg²⁺ reabsorption in this segment is regulated by the Ca²⁺-sensing receptor, parathyroid hormone, and mechanistic target of rapamycin (mTOR) signaling. In the distal convoluted tubule, the fine tuning of Mg²⁺ reabsorption takes place by transcellular Mg²⁺ reabsorption via transient receptor potential melastatin-like types 6 and 7 (TRPM6/TRPM7) divalent cation channels. Activity of TRPM6/TRPM7 is dependent on hormonal regulation, metabolic activity, and interacting proteins. Basolateral Mg²⁺ extrusion is still poorly understood but is probably dependent on the Na⁺ gradient. Cyclin M2 and SLC41A3 are the main candidates to act as Na⁺/Mg²⁺ exchangers. Consequently, disturbances of basolateral Na⁺/K⁺ transport indirectly result in impaired renal Mg²⁺ reabsorption in the distal convoluted tubule. Altogether, this review aims to provide an overview of the molecular mechanisms of Mg²⁺ reabsorption in the kidney, specifically focusing on transgenic mouse models and human hereditary diseases.

The Association of Serum and Dietary Magnesium with Depressive Symptoms

Depression is a leading cause of the global burden of disease and has a multifactorial etiology that includes nutrients. Magnesium status has been associated with depression with inconclusive results. The impact of chronic latent magnesium deficiency (CLMD, 0.75 ≤ serum magnesium < 0.85 mmol/L) on depression has not yet been investigated. We assessed the association between serum magnesium levels/dietary magnesium intake and depressive symptoms by analyzing nationally representative data from Taiwan (Nutrition and Health Survey in Taiwan, NAHSIT). We used the 5-item Brief Symptom Rating Scale to measure depressive symptoms. Subgroup analysis by sex was also performed. Serum magnesium levels had a low correlation with dietary magnesium intake. Higher serum magnesium levels were associated with lower depressive scores and a lower risk of depressive symptoms, but dietary magnesium intake showed no association. Sex differences were found. Compared with subjects with serum magnesium <0.75 mmol/L, those with ≥0.85 mmol/L had lower depressive scores. In conclusion, serum magnesium was inversely associated with depressive symptoms, but dietary magnesium intake was not. Subjects with CLMD showed similar depressive scores and were at a similar risk of depressive symptoms to those with serum magnesium < 0.75 mmol/L. CLMD should be considered while assessing the association between magnesium status and depressive symptoms.

Ionized Magnesium: Interpretation and Interest in Atrial Fibrillation

BACKGROUND

Magnesium (Mg) is often used to manage de novo atrial fibrillation (AF) in the emergency department (ED) and intensive care unit (ICU). Point of care measurement of ionized magnesium (iMg) allows a rapid identification of patients with impaired magnesium status, however, unlike ionized calcium, the interpretation of iMg is not entirely understood. Thus, we evaluated iMg reference values, correlation between iMg and plasmatic magnesium (pMg), and the impact of pH and albumin variations on iMg levels. Secondary objectives were to assess the incidence of hypomagnesemia in de novo AF.

METHODS

A total of 236 emergency department and intensive care unit patients with de novo AF, and 198 control patients were included. Reference values were determined in the control population. Correlation and concordance between iMg and pMg were studied using calcium (ionized and plasmatic) as a control in the whole study population. The impact of albumin and pH was assessed in the discordant iMg and pMg values. Lastly, we assessed the incidence of ionized hypomagnesemia (hypoMg) among de novo AF.

RESULTS

The reference range values established in our study for iMg were: 0.48-0.65 mmol/L (the manufacturers were: 0.45-0.60 mmol/L). A strong correlation was observed between pMg and iMg (r = 0.85), but, unlike for calcium values, there was no significant impact of pH and albumin in iMg/pMg interpretation. The incidence of hypoMg among de novo AF patients was 8.5% (12.7% using our ranges). When using our ranges, we found a significant link (p = 0.01) between hyopMg and hypokalemia.

CONCLUSION

We highlight the need for more accurate reference range values of iMg. Furthermore, our results suggest that blood Mg content is not identical to that of calcium. The incidence of ionized hypomagnesemia among de novo AF patients in our study is 8.5%.

The Role of Hypomagnesemia in Cardiac Arrhythmias: A Clinical Perspective

The importance of magnesium (Mg2+), a micronutrient implicated in maintaining and establishing a normal heart rhythm, is still controversial. It is known that magnesium is the cofactor of 600 and the activator of another 200 enzymatic reactions in the human organism. Hypomagnesemia can be linked to many factors, causing disturbances in energy metabolism, ion channel exchanges, action potential alteration and myocardial cell instability, all mostly leading to ventricular arrhythmia. This review article focuses on identifying evidence-based implications of Mg2+ in cardiac arrhythmias. The main identified benefits of magnesemia correction are linked to controlling ventricular response in atrial fibrillation, decreasing the recurrence of ventricular ectopies and stopping episodes of the particular form of ventricular arrhythmia called torsade de pointes. Magnesium has also been described to have beneficial effects on the incidence of polymorphic ventricular tachycardia and supraventricular tachycardia. The implication of hypomagnesemia in the genesis of atrial fibrillation is well established; however, even if magnesium supplementation for rhythm control, cardioversion facility or cardioversion success/recurrence of AF after cardiac surgery and rate control during AF showed some benefit, it remains controversial. Although small randomised clinical trials showed a reduction in mortality when magnesium was administered to patients with acute myocardial infarction, the large randomised clinical trials failed to show any benefit of the administration of intravenous magnesium over placebo.