Comment on: Magnesium Depletion Score Predicts Diabetic Retinopathy Risk Among Diabetes: Findings from NHANES 2005-2018

I read the work by Yuan Chen et al. Biol Trace Elem Res 201(6):2750-2756 2023 entitled "Magnesium depletion score predicts diabetic retinopathy risk among diabetes: findings from NHANES 2005-2018" which was published in the Biological Trace Element Research (volume 201, issue 6, June 2023), with great interest. The authors specified that magnesium depletion score was associated with diabetic retinopathy. However, there are some limitations that should be addressed properly: first, the correct diagnosis of diabetic retinopathy; second, the consideration for statistical method; and third, the conclusion drawn from this study. I believe there are a few points regarding study design and conclusion that, if addressed, would improve the quality of this article.

A Rare Case of Neonatal Hypomagnesemia with Secondary Hypocalcemia Caused by a Novel Homozygous TRPM6 Gene Variant

BACKGROUND Familial hypomagnesemia with secondary hypocalcemia (HSH) is a rare autosomal recessive disorder (OMIM# 602014) caused by mutations in the gene encoding transient receptor potential melastatin 6 (TRPM6)) on chromosome 9q22, a channel involved in epithelial magnesium resorption. While a plethora of studies have delineated various clinical manifestations pertinent to this mutation, the literature is devoid of connections between TRPM6 mutations and bleeding diathesis, or sudden infant death syndrome (SIDS). This report presents a case of familial HSH associated with the novel homozygous TRPM6 gene variant c.5281C>G p. (Arg1761Gly) chr9: 77354845. CASE REPORT This report details a 26-day-old neonate, born full term with optimal Apgar scores, who experienced an abrupt emergence of apnea, cyanosis, bilateral nasal bleeding, and diminished alertness. Despite the neonate's initially unremarkable clinical birth indicators, a meticulous assessment unveiled a pronounced family history of SIDS, including a sibling previously diagnosed with hypomagnesemia. Laboratory examination of the infant demonstrated severe hypomagnesemia and hypocalcemia, conditions which were promptly ameliorated following intravenous administration of magnesium and calcium. Whole-exome sequencing identified a homozygous TRPM6 gene mutation c.5281C>G p. (Arg1761Gly) at chr9: 77354845. This gene is crucial for magnesium regulation. The mutation involves a cytosine-to-guanine shift, resulting in an arginine to glycine amino acid substitution at position 1761 of the TRPM6 protein. CONCLUSIONS This report has highlighted that infantile hypomagnesemia may be associated with symptoms and signs that can mimic infection, or it can present with seizures. Although familial HSH is a rare genetic disorder that can be identified by genetic testing, correction of hypomagnesemia is the most important and immediate clinical management strategy.

Improving diagnosis and treatment of hypomagnesemia

Magnesium is one of the most abundant cations in the body and acts as a cofactor in more than 600 biochemical reactions. Hypomagnesemia is a highly prevalent condition, especially in subjects with comorbid conditions, but has received less attention than other electrolyte disturbances. This review will discuss magnesium physiology, absorption, storage, distribution across the body, and kidney excretion. After reviewing the regulation of magnesium homeostasis, we will focus on the etiology and clinical presentation of hypomagnesemia. The role of laboratory medicine in hypomagnesemia will be the main purpose of this review, and we will discuss the laboratory tests and different samples and methods for its measurement. Although free magnesium is physiologically active, total serum magnesium is the most commonly used measurement in laboratory medicine and is apt for clinical purposes; however, it is not appropriately used, and many patients with hypomagnesemia remain undiagnosed and not treated. Using information technologies, laboratory medicine can largely improve the diagnosis and treatment of hypomagnesemia through the design and establishment of automatic demand management and result management interventions by acting in the first and last steps of the laboratory cycle, test requests, and actions taken after test results, to unmask patients with hypomagnesemia and improve the number of patients undergoing treatment.

[Severe hypomagnesemia in a man with alcohol dependence: a forgotten electrolyte in a neglected population]

BACKGROUND

Symptoms of acute alcohol withdrawal like tremors, seizures and delirium are commonly treated with benzodiazepines and vitamins. When complaints are not reacting to this treatment, an alternative diagnosis must be considered. Although hypomagnesemia is present in at least 30 percent of the patients with alcohol dependence, it can provoke and maintain these complaints.

CASE DESCRIPTION

We present a 43-year-old man with alcohol dependence, who shows neurological, muscular, and cardiac consequences of an undiagnosed hypomagnesemia.

CONCLUSION

In daily clinical practice there is not enough attention for magnesium deficits, especially in patients with alcohol dependence. Serious complications can be prevented by recognizing and treating magnesium deficiency more adequately.

[Neurological symptoms of hypomagnesemia]

BACKGROUND

An epileptic seizure is a common neurological presentation in the Emergency Department (ED). Electrolyte disturbances are an important cause of neurological symptoms like seizures and hypomagnesemia is one of them. PPI's can cause hypomagnesemia and are readily prescribed. Therefore patients taking PPI's are at risk of developing neurological symptoms due to hypomagnesemia.

CASE

A 82-year old woman was seen in ED with a history of nausea, vomiting and vertigo. A vertical nystagmus was observed with attacks of mydriasis followed by a phase of encephalopathy and restlessness. These were recognized as epilepsy. Hypokaliemia, hypocalcemia and a deep hypomagnesemia were present. The PPI accounted for hypomagnesemia. After 2 days of intravenous magnesium suppletion all symptoms disappeared.

CONCLUSION

PPI's can cause hypomagnesemia and magnesium levels should be obtained in patients presenting with encephalopathy or atypical neurological symptoms.

[Hypomagnesemia in newborns with hypoxic ischemic encephalopathy and whole-body hypothermia]

INTRODUCTION

In newborns with the diagnosis of hypoxic-ischemic encephalopathy (HIE) treated with hypother mia, metabolic alterations are observed, which are associated with neurological prognosis. Hypo magnesemia has been reported frequently in the literature in these patients, but it is not measured or corrected in all neonatal healthcare centers.

OBJECTIVE

To evaluate the frequency of hypomag nesemia and hypocalcemia in newborns with HIE treated with whole-body hypothermia and to evaluate the response to the magnesium sulfate administration.

PATIENTS AND METHOD

Prospective, observational and descriptive study in hospitalized newborns with the diagnosis of HIE and trea ted with whole-body hypothermia between the years 2016 and 2017. Serial blood measurement of magnesemia (Mg) and calcemia (Ca) was performed. When presenting an Mg level < 1.8 mg/dl, supplementation with magnesium sulfate was administered to maintain levels between 1.9 and 2.8 mg/dl. The frecuency of hypomagnesemia, hypocalcemia and clinical evolution was registered. A descriptive statistical analysis was performed, with central tendency measures.

RESULTS

Sixteen ca ses were included, 13 of them presented hypomagnesemia (81.3%), with early-onset (6-36 hours of life), which was normalized with magnesium sulfate treatment, receiving a second dose 4 patients. Six of 16 patients presented hypocalcemia (37.5 %).

CONCLUSIONS

Hypomagnesemia is frequent (80%), similar to that described in the literature, and should be controlled and corrected early, given its physiological role, in the same way that calcium is controlled.

A patient with extensive cerebral calcification due to pseudohypoparathyroidism: a case report

BACKGROUND

Pseudohypoparathyroidism(PHP) is a heterogeneous group of disorders due to impaired activation of c AMP dependant pathways following binding of parathyroid hormone (PTH) to its receptor. In PHP end organ resistance to PTH results in hypocalcaemia, hyperphosphataemia and high PTH levels.

CASE PRESENTATION

A 59 year old male presented with a history of progressive impairment of speech and unsteadiness of gait for 1 week and acute onset altered behavior for 1 day and one episode of generalized seizure. His muscle power was grade four according to MRC (medical research council) scale in all limbs and Chovstek's and Trousseau's signs were positive. Urgent non contrast computed tomography scan of the brain revealed extensive bilateral cerebral and cerebellar calcifications. A markedly low ionized calcium level of 0.5 mmol/l, an elevated phosphate level of 9.5 mg/dl (reference range: 2.7-4.5 mg/dl) and an elevated intact PTH of 76.3 pg/l were noted. His renal functions were normal. His hypocalcemia was accentuated by the presence of hypomagnesaemia. His 25 hydroxy vitamin D level was only marginally low which could not account for severe hypocalcaemia. A diagnosis of pseudohypoparathyroidism without phenotypic defects, was made due to hypocalcaemia and increased parathyroid hormone levels with cerebral calcifications. The patient was treated initially with parenteral calcium which was later converted to oral calcium supplements. His coexisting Vitamin D deficiency was corrected with 1αcholecalciferol escalating doses. His hypomagnesaemia was corrected with magnesium sulphate parenteral infusions initially and later with oral preparations. With treatment there was a significant clinical and biochemical response.

CONCLUSION

Pseudohypoparathyroidism can present for the first time in elderly resulting in extensive cerebral calcifications. Identification and early correction of the deficit will result in both symptomatic and biochemical response.

[A patient with inflammatory arthralgia, paraesthesia and atrial fibrillation]

A 61-year-old male patient had suffered from inflammatory arthralgia since 2014 and had been taking a proton pump inhibitor (PPI) for many years. Additionally, the patient was prescribed apixaban for atrial fibrillation. The blood tests on admission showed a marked hypomagnesemia with secondary hypocalcemia and hypokalemia. After discontinuation of the PPI and through substitution of magnesium, the blood results normalized completely and the patient was finally symptom-free. This case report underlines the important role of magnesium in rheumatology and presents the various mechanisms of action of magnesium.

Refeeding Syndrome

Refeeding syndrome describes the metabolic disturbances and clinical sequelae that occur in response to nutritional rehabilitation of patients who are moderate to severely malnourished. When risk factors are not identified and nutrition therapy is not managed appropriately, devastating consequences such as electrolyte depletion and imbalances, fluid overload, arrhythmia, seizure, encephalopathy, and death may occur. As this entity is often unrecognized, especially in pediatrics, becoming familiar with the pathophysiology, clinical manifestations, and management strategies will help clinicians caring for children avoid unnecessary morbidity and mortality. [Pediatr Ann. 2019;48(11):e448-e454.].

Differences in Serum Magnesium Levels in Diabetic and Non-Diabetic Patients Following One-Anastomosis Gastric Bypass

Patients with obesity and type 2 diabetes mellitus (T2DM) are regarded to have reduced serum magnesium (Mg) concentrations. We aimed to assess the changes in serum Mg concentrations at 12-month follow-up in patients, with and without T2DM, who underwent one anastomosis gastric bypass surgery. Overall, 50 patients (80% female, age 42.2 (12.5) years) with morbid obesity (mean baseline BMI 43.8 (4.3) kg/m2) were included in the analysis. Half of the included patients had T2DM diagnosed at baseline, and these patients showed lower serum Mg concentration (0.78 (0.07)) vs. 0.83 (0.05) mmol/L; p = 0.006), higher blood glucose levels (129.9 (41.3) vs. 87.6 (8.1) mg/dL; p < 0.001) as well as HbA1c concentrations (6.7 (1.4) vs. 5.3 (0.5)%; p < 0.001). During follow-up, BMI and glucose levels showed a decrease; however, serum Mg levels remained stable. At baseline 42% of patients were found to be Mg deficient, which was reduced to 33% at six months and to 30% at 12 months follow-up. Moreover, patients with T2DM had an odds ratio of 9.5 (95% CI = 3.0-29.7; p < 0.001) for magnesium deficiency when compared to patients without T2DM. Further research into the role of Mg and its role in T2DM and other obesity-related comorbidities are needed.

Magnesium: Are We Consuming Enough?

Magnesium is essential for maintaining normal cellular and organ function. In-adequate magnesium balance is associated with various disorders, such as skeletal deformities, cardiovascular diseases, and metabolic syndrome. Unfortunately, routinely measured serum magnesium levels do not always reflect total body magnesium status. Thus, normal blood magnesium levels eclipse the wide-spread magnesium deficiency. Other magnesium measuring methods, including the magnesium loading test, may provide more accurate reflections of total body magnesium status and thus improve identification of magnesium-deficient individuals, and prevent magnesium deficiency related complications.

Control of metabolic predisposition to cardiovascular complications of chronic kidney disease by effervescent calcium magnesium citrate: a feasibility study

Aims

Cardiovascular (CV) complications are common in chronic kidney disease (CKD). Numerous metabolic disturbances including hyperphosphatemia, high circulating calciprotein particles (CPP), hyperparathyroidism, metabolic acidosis, and magnesium deficiency are associated with, and likely pathogenic for CV complications in CKD. The goal of this feasibility study was to determine whether effervescent calcium magnesium citrate (EffCaMgCit) ameliorates the aforementioned pathogenic intermediates.

Methods

Nine patients with Stage 3 and nine patients with Stage 5D CKD underwent a randomized crossover study, where they took EffCaMgCit three times daily for 7 days in one phase, and a conventional phosphorus binder calcium acetate (CaAc) three times daily for 7 days in the other phase. Two-hour postprandial blood samples were obtained on the day before and on the 7th day of treatment.

Results

In Stage 5D CKD, EffCaMgCit significantly increased T50 (half time for conversion of primary to secondary CPP) from baseline by 63% (P = 0.013), coincident with statistically non-significant declines in serum phosphorus by 25% and in saturation of octacalcium phosphate by 35%; CaAc did not change T50. In Stage 3 CKD, neither EffCaMgCit nor CaAc altered T50. With EffCaMgCit, a significant increase in plasma citrate was accompanied by statistically non-significant increase in serum Mg and phosphate. CaAc was without effect in any of these parameters in Stage 3 CKD. In both Stages 3 and 5D, both drugs significantly reduced serum parathyroid hormone. Only EffCaMgCit significantly increased serum bicarbonate by 3 mM (P = 0.015) in Stage 5D.

Conclusions

In Stage 5D, EffCaMgCit inhibited formation of CPP, suppressed PTH, and conferred magnesium and alkali loads. These effects were unique, since they were not observed with CaAc. In Stage 3 CKD, neither of the regimens have any effect. These metabolic changes suggest that EffCaMgCit might be useful in protecting against cardiovascular complications of CKD by ameliorating pathobiologic intermediates.

Chronic magnesium deficiency and human disease; time for reappraisal?

Numerous epidemiological, experimental and clinical studies over the last 30 years have consistently shown that chronic magnesium deficiency is associated with and/or exacerbates a number of major disorders (Table 1). Yet chronic magnesium deficiency is not widely recognized and a major reason for this failure is that serum magnesium levels do not accurately reflect body magnesium stores. Specifically, in chronic magnesium deficiency, serum magnesium levels are often within the normal reference range (usually lowest quartile) and may not progress to overt hypomagnesaemia. This raises serious questions namely (i) should chronic magnesium deficiency be considered in high-risk patients irrespective of serum magnesium, even when 'normal'? and (ii) if recognized, should oral magnesium supplement be given to restore body stores? Appreciating the vital role of magnesium for normal cellular function and bone health may help in formulating a well-considered and justifiable approach to these questions. Pragmatic tests for assessing magnesium status in the adult are suggested and discussed.

Challenges in the Diagnosis of Magnesium Status

Magnesium is a critical mineral in the human body and is involved in ~80% of known metabolic functions. It is currently estimated that 60% of adults do not achieve the average dietary intake (ADI) and 45% of Americans are magnesium deficient, a condition associated with disease states like hypertension, diabetes, and neurological disorders, to name a few. Magnesium deficiency can be attributed to common dietary practices, medications, and farming techniques, along with estimates that the mineral content of vegetables has declined by as much as 80⁻90% in the last 100 years. However, despite this mineral's importance, it is poorly understood from several standpoints, not the least of which is its unique mechanism of absorption and sensitive compartmental handling in the body, making the determination of magnesium status difficult. The reliance on several popular sample assays has contributed to a great deal of confusion in the literature. This review will discuss causes of magnesium deficiency, absorption, handling, and compartmentalization in the body, highlighting the challenges this creates in determining magnesium status in both clinical and research settings.

Higher Dietary Magnesium Intake and Higher Magnesium Status Are Associated with Lower Prevalence of Coronary Heart Disease in Patients with Type 2 Diabetes

In type 2 diabetes mellitus (T2D), the handling of magnesium is disturbed. Magnesium deficiency may be associated with a higher risk of coronary heart disease (CHD). We investigated the associations between (1) dietary magnesium intake; (2) 24 h urinary magnesium excretion; and (3) plasma magnesium concentration with prevalent CHD in T2D patients. This cross-sectional analysis was performed on baseline data from the DIAbetes and LifEstyle Cohort Twente-1 (DIALECT-1, n = 450, age 63 ± 9 years, 57% men, and diabetes duration of 11 (7-18) years). Prevalence ratios (95% CI) of CHD by sex-specific quartiles of magnesium indicators, as well as by magnesium intake per dietary source, were determined using multivariable Cox proportional hazard models. CHD was present in 100 (22%) subjects. Adjusted CHD prevalence ratios for the highest compared to the lowest quartiles were 0.40 (0.20, 0.79) for magnesium intake, 0.63 (0.32, 1.26) for 24 h urinary magnesium excretion, and 0.62 (0.32, 1.20) for plasma magnesium concentration. For every 10 mg increase of magnesium intake from vegetables, the prevalence of CHD was, statistically non-significantly, lower (0.75 (0.52, 1.08)). In this T2D cohort, higher magnesium intake, higher 24 h urinary magnesium excretion, and higher plasma magnesium concentration are associated with a lower prevalence of CHD.

[Features of a drinking regimen and signs of deficiency of magnesium at elderly patients with removable stomatologic orthopedic constructions.]

The purpose was to study features of a drinking regimen and signs of deficiency of magnesium at elderly patients with removable stomatologic orthopedic constructions. Questioning of 1 388 elderly patients who coming for the dentistry office. Patients were divided into three groups: the 1st was characterized by existence only of fixed stomatologic orthopedic constructions (n=419); the 2nd group was characterized by existence of partially removable constructions (n=512); the 3rd group was characterized by existence of full-removable constructions (n=457). We defined symptoms of the central obesity as rising of BMI and a circle of a waist. Patients were tested for possible deficiency of magnesium. At patients of the 3rd group have more often symptoms of the central obesity, than at the 1st and 2nd groups (52,5% against 21,5 and 41,8%, p<0.05). Patients of the 3rd group have more often signs of deficiency of magnesium, than other patients (62,3% against 11,7 and 22,3%, p<0.05). Patients of the 3rd group more often than others intake cocoa (54,1% against 5,7 and 10,4%, p<0.05), carbonated drinks (24,5% against 7,6 and 4,3%, p<0,05), hard alcoholic beverages (23% against 10 and 10,2%, p<0,05). All elderly patients extremely seldom use bottled water.

A case of osteomalacia due to deranged mineral balance caused by saccharated ferric oxide and short-bowel syndrome: A case report

RATIONALE

Saccharated ferric oxide has been shown to lead to elevation of fibroblast growth factor 23, hypophosphatemia, and, consequently, osteomalacia. Moreover, mineral imbalance is often observed in patients with short-bowel syndrome to some degree.

PATIENT CONCERNS

A 62-year-old woman with short-bowel syndrome related with multiple resections of small intestines due to Crohn disease received regular intravenous administration of saccharated ferric oxide. Over the course of treatment, she was diagnosed with tetany, which was attributed to hypocalcemia. Additional assessments of the patient revealed not only hypocalcemia, but also hypophosphatemia, hypomagnesemia, osteomalacia, and a high concentration of fibroblast growth factor 23 (314 pg/mL).

DIAGNOSES

We diagnosed her with mineral imbalance-induced osteomalacia due to saccharated ferric oxide and short-bowel syndrome.

INTERVENTIONS

Magnesium replacement therapy and discontinuation of saccharated ferric oxide alone.

OUTCOMES

These treatments were able to normalize her serum mineral levels and increase her bone mineral density.

LESSONS

This case suggests that adequate evaluation of serum minerals, including phosphate and magnesium, during saccharated ferric oxide administration may be necessary, especially in patients with short-bowel syndrome.

Data from Controlled Metabolic Ward Studies Provide Guidance for the Determination of Status Indicators and Dietary Requirements for Magnesium

Determination of whether magnesium (Mg) is a nutrient of public health concern has been hindered by questionable Dietary Recommended Intakes (DRIs) and problematic status indicators that make Mg deficiency assessment formidable. Balance data obtained since 1997 indicate that the EAR and RDA for 70-kg healthy individuals are about 175 and 250 mg/day, respectively, and these DRIs decrease or increase based on body weight. These DRIs are less than those established for the USA and Canada. Urinary excretion data from tightly controlled metabolic unit balance studies indicate that urinary Mg excretion is 40 to 80 mg (1.65 to 3.29 mmol)/day when Mg intakes are <250 mg (10.28 mmol)/day, and 80 to 160 mg (3.29 to 6.58 mmol)/day when intakes are >250 mg (10.28 mmol)/day. However, changing from low to high urinary excretion with an increase in dietary intake occurs within a few days and vice versa. Thus, urinary Mg as a stand-alone status indicator would be most useful for population studies and not useful for individual status assessment. Tightly controlled metabolic unit depletion/repletion experiments indicate that serum Mg concentrations decrease only after a prolonged depletion if an individual has good Mg reserves. These experiments also found that, although individuals had serum Mg concentrations approaching 0.85 mmol/L (2.06 mg/dL), they had physiological changes that respond to Mg supplementation. Thus, metabolic unit findings suggest that individuals with serum Mg concentrations >0.75 mmol/L (1.82 mg/L), or as high as 0.85 mmol/L (2.06 mg/dL), could have a deficit in Mg such that they respond to Mg supplementation, especially if they have a dietary intake history showing <250 mg (10.28 mmol)/day and a urinary excretion of <80 mg (3.29 mmol)/day.

Dose-Response Relationship between Dietary Magnesium Intake and Risk of Type 2 Diabetes Mellitus: A Systematic Review and Meta-Regression Analysis of Prospective Cohort Studies

The epidemiological evidence for a dose-response relationship between magnesium intake and risk of type 2 diabetes mellitus (T2D) is sparse. The aim of the study was to summarize the evidence for the association of dietary magnesium intake with risk of T2D and evaluate the dose-response relationship. We conducted a systematic review and meta-analysis of prospective cohort studies that reported dietary magnesium intake and risk of incident T2D. We identified relevant studies by searching major scientific literature databases and grey literature resources from their inception to February 2016. We included cohort studies that provided risk ratios, i.e., relative risks (RRs), odds ratios (ORs) or hazard ratios (HRs), for T2D. Linear dose-response relationships were assessed using random-effects meta-regression. Potential nonlinear associations were evaluated using restricted cubic splines. A total of 25 studies met the eligibility criteria. These studies comprised 637,922 individuals including 26,828 with a T2D diagnosis. Compared with the lowest magnesium consumption group in the population, the risk of T2D was reduced by 17% across all the studies; 19% in women and 16% in men. A statistically significant linear dose-response relationship was found between incremental magnesium intake and T2D risk. After adjusting for age and body mass index, the risk of T2D incidence was reduced by 8%–13% for per 100 mg/day increment in dietary magnesium intake. There was no evidence to support a nonlinear dose-response relationship between dietary magnesium intake and T2D risk. The combined data supports a role for magnesium in reducing risk of T2D, with a statistically significant linear dose-response pattern within the reference dose range of dietary intake among Asian and US populations. The evidence from Europe and black people is limited and more prospective studies are needed for the two subgroups.

Hypoxic-Ischemic Encephalopathy and Serum Magnesium Monitoring and Maintenance

Magnesium plays important roles in many physiologic functions including protein synthesis, bone development, and cell membrane function. There is some evidence to suggest a role for magnesium sulfate as a therapeutic neuroprotective agent along with therapeutic hypothermia in infants with hypoxic-ischemic encephalopathy, but studies are inconclusive. Ischemic insult and hypothermia may both play a role in altered magnesium levels in this population.

Magnesium in Prevention and Therapy

Magnesium is the fourth most abundant mineral in the body. It has been recognized as a cofactor for more than 300 enzymatic reactions, where it is crucial for adenosine triphosphate (ATP) metabolism. Magnesium is required for DNA and RNA synthesis, reproduction, and protein synthesis. Moreover, magnesium is essential for the regulation of muscular contraction, blood pressure, insulin metabolism, cardiac excitability, vasomotor tone, nerve transmission and neuromuscular conduction. Imbalances in magnesium status—primarily hypomagnesemia as it is seen more common than hypermagnesemia—might result in unwanted neuromuscular, cardiac or nervous disorders. Based on magnesium’s many functions within the human body, it plays an important role in prevention and treatment of many diseases. Low levels of magnesium have been associated with a number of chronic diseases, such as Alzheimer’s disease, insulin resistance and type-2 diabetes mellitus, hypertension, cardiovascular disease (e.g., stroke), migraine headaches, and attention deficit hyperactivity disorder (ADHD).

Hypermagnesemia is a strong independent risk factor for mortality in critically ill patients: results from a cross-sectional study

BACKGROUND

Patients with electrolyte imbalances or disorders have a high risk of mortality. It is unknown if this finding from sodium or potassium disorders extends to alterations of magnesium levels.

METHODS AND PATIENTS

In this cross-sectional analysis, all emergency room patients between 2010 and 2011 at the Inselspital Bern, Switzerland, were included. A multivariable logistic regression model was performed to assess the association between magnesium levels and in-hospital mortality up to 28days.

RESULTS

A total of 22,239 subjects were screened for the study. A total of 5339 patients had plasma magnesium concentrations measured at hospital admission and were included into the analysis. A total of 6.3% of the 352 patients with hypomagnesemia and 36.9% of the 151 patients with hypermagnesemia died. In a multivariate Cox regression model hypermagnesemia (HR 11.6, p<0.001) was a strong independent risk factor for mortality. In these patients diuretic therapy revealed to be protective (HR 0.5, p=0.007). Hypomagnesemia was not associated with mortality (p>0.05). Age was an independent risk factor for mortality (both p<0.001).

CONCLUSION

The study does demonstrate a possible association between hypermagnesemia measured upon admission in the emergency department, and early in-hospital mortality.

Dysmagnesemia in Hospitalized Patients: Prevalence and Prognostic Importance

OBJECTIVE

To examine the prevalence of serum magnesium (Mg) alterations and outcomes in hospitalized patients.

PATIENTS AND METHODS

All admissions to Mayo Clinic in Rochester, Minnesota, from January 1, 2009, through December 31, 2013 (288,120 patients), were screened. Admission Mg from each unique patient and relevant clinical data were extracted from the institutional electronic database.

RESULTS

After excluding patients aged less than 18 years, those without Mg measurement, and readmission episodes, a total of 65,974 patients were studied. Magnesium levels of 2.1 mg/dL or higher were found in 20,777 patients (31.5%), and levels less than 1.7 mg/dL were noted in 13,320 (20.2%). Hypomagnesemia was common in patients with hematologic/oncological disorders, and hypermagnesemia was common in those with cardiovascular disease. The lowest hospital mortality, assessed by restricted cubic spline and percentage death, occurred in patients with Mg levels between 1.7 and 1.89 mg/dL. An Mg level of less than 1.7 mg/dL was independently associated with an increased risk of hospital mortality after adjusting for all variables except the admission diagnosis; risk for longer hospital stay and being discharged to a care facility were increased in the fully adjusted model. An elevated Mg level of 2.3 mg/dL or higher was a predictor for all adverse outcomes. The magnitude of Mg elevations in patients with levels of 2.3 mg/dL or higher (N=7908) was associated with worse hospital mortality in a dose-response manner. In patients with cardiovascular diseases, Mg levels of 1.5 to 1.69 mg/dL and 2.3 mg/dL or higher both independently predicted poor outcomes including hospital mortality.

CONCLUSION

Dysmagnesemia in hospitalized patients is common, with hypermagnesemia being most prevalent. Compared with hypomagnesemia, hypermagnesemia is a stronger predictor for poor outcomes. Magnesium supplementation for patients without Mg deficiency should be avoided in the absence of randomized controlled trials documenting a benefit.

[Short bowel syndrome cause of hypomagnesaemia importance of its diagnosis and treatment]

The short bowel syndrome (SIC) is a complex entity characterized by a malabsorptive state usually secondary to extensive intestinal resection originating a clinical, metabolic and/or nutritional disorder due to the reduction of the effective intestinal absorptive surface. The diagnosis is essentially clinical and, due to the patients malabsorptive process, it requires nutritional support to maintain their basic requirements, as the case reported. The clinical features of SIC patients depend on the grade of the alteration of function of the the small intestine or the impairment secondary to the surgical resection. We know that electrolytes are absorbed predominantly in the proximal gut. The regulation of ion/mineral levels depend on both the intestinal absorption and the renal excretion. We present an unusual case of SIC with only low absorption of magnesium. We discuss the most outstanding aspects of the case and review the literature.

[Magnesium and cardiovascular disease: new data and perspectives]

Presented data are intended to draw the attention of clinicians to question the importance of timely diagnosis deficiency of magnesium states and their timely correction of both patients by providing dietary guidelines and prescribing magnesium for preventive and therapy purposes.

Delayed Onset of Ataxia in a Patient with Short Bowel Syndrome: A Case of Vitamin E Deficiency

Chronic gastrointestinal disease can result in nutritional deficiencies that can have a direct effect on the neurologic system. Although acute abnormalities can be corrected, symptoms are rarely reversible. Recognizing the appropriate abnormality is a crucial part of long-term treatment strategies in this population. Because motor and cerebellar symptoms can contribute to poor feeding, aggressive supplementation should begin as soon as symptoms are recognized. We present a patient with delayed onset and progressive hypovitaminosis E and briefly review diagnostic and therapeutic options.

[Unusual alcoholic weaning, complicated: do you check the blood phosphate?]

A 65 year old alcoholic man was hospitalized because he was tired, hypotonic, with postural tremor. The neurologic symptoms increased during the first two days despite an adequate therapy for alcoholic weaning with hydratation, benzodiazepines and vitamins. A severe hypophosphatemia is diagnosed, associated with hypovitaminosis D, mild hypomagnesemia, mild hypokaliemia and a refeeding syndrome. 24 hours after the normalisation of his phosphatemia, the neurologic symptoms are adjusted.

[Magnesium homeostasis disorders: hypomagnesemia]

Physiologically, magnesium plays an essential role in bone formation, neuromuscular stability and muscle contraction, and the consequences of its altered homeostasis may be serious. Magnesium deficiency and hypomagnesemia are common and under-recognized problems, which can cause a variety of symptoms and can also affect the other cations metabolism. In this review causes, clinical picture and management of hypomagnesemia and magnesium deficiency are discussed.

[Hypomagnesemia and proton pump inhibitors]

Magnesium (Mg2+) is the second intracellular cation after potassium and is an important cofactor in cellular enzymatic reactions. Its homeostasis is essential for many cells including those of the nervous system, cardiomyocytes and smooth or striated muscle cells. The balance of serum Mg2+ depends mainly on its intestinal absorption and its excretion by the renal distal convoluted tubule. While many etiologies including genetic diseases have been described as sources of imbalance in serum Mg2+, the occurrence of hypomagnesaemia during proton pump inhibitors (PPIs) treatment is rarely reported. The pathogenesis is poorly understood, and might be due to a decrease in intestinal absorption of Mg2+ during IPPs treatment.

[To start eating again could be dangerous]

A 36-year-old woman with anorexia nervosa and resulting malnutrition decided to change her life and eat properly. One day after the refeeding start, instead of feeling better she felt much worse: fatigue, nausea and leg swelling occurred. She consulted our emergency department. A «refeeding syndrome» has been diagnosed. In this case report we discuss causes, clinical presentation and treatment of this illness. The aim is to make practitians aware about the existing of this disease even with oral refeeding. Warning signs have to be interpreted correctly in order to avoid dramatic consequences.

[Magnesium deficiency and anxiety-depressive syndrome in elderly patients with chronic heart failure]

The combination of a magnesium deficiency, heart failure and anxiety-depressive disorders are accompanied by the imposition of symptoms, differential diagnosis difficulties and requires special attention in treating elderly and senile patients. The study of 74 patients with chronic heart failure of 60 to 95 years in urban medical district revealed that the majority of people had depressive disorders, disturbances of electrical stability of the heart in the form of increasing the duration of the QT interval and magnesium deficiency. Frequency and severity of the latter increase with age, increase of a functional class of heart failure, worsening the severity of anxiety-depressive syndrome and prolongation QT.

Magnesium and the acute physician

Magnesium deficiency, and to a lesser extent magnesium excess, is commonly encountered in patients admitted to the Acute Medical Unit. It is important that acute physicians are able to identify those at risk of these states and initiate appropriate investigation and treatment. This article aims to provide the reader with a sound understanding of magnesium physiology and its effect at a cellular level. The causes, symptoms and treatment of magnesium disorders are discussed along with a review of evidence regarding the therapeutic use of magnesium.

How should hypomagnesaemia be investigated and treated?

Hypomagnesaemia is relatively common, with an estimated prevalence in the general population ranging from 2·5% to 15%. It may result from inadequate magnesium intake, increased gastrointestinal or renal loss or redistribution from extracellular to intracellular space. Drug-induced hypomagnesaemia, particularly related to proton pump inhibitor (PPI) therapy, is being increasingly recognized. Most patients with hypomagnesaemia are asymptomatic; symptomatic magnesium depletion is often associated with multiple other biochemical abnormalities, including hypokalaemia, hypocalcaemia and metabolic acidosis. Manifestations of symptomatic hypomagnesaemia most often involve neuromuscular, cardiovascular and metabolic features. Patients with symptomatic hypomagnesaemia should be treated with intravenous magnesium, reserving oral replacement for asymptomatic patients.

Relation between serum magnesium level and migraine attacks

OBJECTIVE

The determination of serum magnesium levels in migraine.

METHODS

In a case control study performed between January 2007 and December 2007 at Tabriz University of Medical Sciences, Tabriz, Iran, 140 migraine patients were enrolled and their level of serum magnesium was determined and the results were compared with 140 healthy people who did not have any headache, kidney, or gastrointestinal disorders, and no consumption of magnesium complements.

RESULTS

Migraine patients (22 male, 118 female) with a mean age of 33.82+/-10.31 and 140 healthy people (26 male, 114 female) with a mean age of (34.19+/-9.95) were enrolled. Forty patients had aura and 100 patients did not have aura. The average serum magnesium level in the patient group (26.14+/-4.3) was significantly lower than the control (31.09+/-4.32) group (p=0.000). There was no significant difference between the mean level of serum magnesium in patients with migraine with aura and without aura, however, there was a significant linear relationship between the amount of serum magnesium and the frequency of headache.

CONCLUSION

Serum magnesium in migraine patients was significantly lower than the normal population and related to the frequency of migraine attacks, supporting the use of magnesium in prevention and treatment of migraine.

Magnesium deficiency in heart failure patients with diabetes mellitus

OBJECTIVE

To assess the serum magnesium level in heart failure patients with diabetes mellitus.

METHODS

A case-control study was conducted at Basic Medical Sciences Institute (BMSI), Jinnah Postgraduate Medical Centre (JPMC), Karachi, in collaboration with National Institute of Cardiovascular Diseases (NICVD), Karachi, from April 2003 to December 2003. The study included 45 diagnosed cases of heart failure with diabetes mellitus, between the age group 35-65 years. Serum magnesium and glucose levels were estimated and compared by using the student "t" test and p value (<0.01, <0.05, <0.001) were used to analyze the statistical significance.

RESULTS

Out of 45 cases of heart failure, 15 were diabetic. Of these, eleven (73.3%) had low serum magnesium (<1.8 mg/dl), one (6.7%) was within normal range (1.8-2.0 mg/dl) and three (20%) were in the high level range(>2.0 mg/dl).

CONCLUSION

The study showed low serum magnesium level in heart failure patients with diabetes mellitus.

Quadriparesis in an adult--Gitelman syndrome

A 24 years old soldier presented with sudden onset of weakness in all four limbs. There was no history of any antecedent respiratory infection, fever, diarrhoea or vomiting. Neurological examination of limbs revealed reduced tone and power in all limbs. Although the tendon reflexes were diminished they could be elicited in all limbs. Rest of the clinical examination was unremarkable. Serum potassium was 2.1 mmol/l, sodium 138 mmol/l, bicarbonate 35.3 mmol/l, urea 5.7 mmol/l, creatinine 69 umol/l and serum creatine kinase (CK) was 686 U/l. Power in the patient's limbs gradually improved to normal by following afternoon after potassium chloride infusion. Serum chloride was 93 mmol/l, bicarbonate 33.4 mmol/l, calcium 2.1 mmol/l, urine sodium 134 mmol/l, urine potassium 82 mmol/l, urine chloride 156 mmol/l and urine pH 6.0. Urinary calcium excretion was 2.2 mmol in 24 hours. Serum magnesium was 0.7 mmol/l. A diagnosis of Gitelman syndrome was made. He is doing well on spironolactone, potassium chloride supplementation and high sodium diet, maintaining serum potassium level between 3.5 and 4.5 mmol/l.

Diagnosis and clinical approach in Gitelman's syndrome

Hypokalemia, defined as a plasma potassium concentration <3.5 mmol/l, is the most common electrolyte abnormality encountered in our clinical practice. Unfortunately, in many cases, the etiologies were unclear and resulted in a wrong treatment. Indeed, the true etiology could be such a 'rare' one and could be found by doing a comprehensive work up. One of this is Gitelman's syndrome, a rare genetic disorder characterized by hypokalemic alkalosis, hypomagnesemia, hypocalciuria, and secondary aldosteronism without hypertension. Since this disorder is found in 1% Caucasian populations, this is one of the most frequently inherited renal tubular disorders. A 27 year old man came to emergency room with weakness and generalised muscle cramps. He was investigated three months before for a similar electrolyte disturbance which was found to be inconclusive. The routine laboratory data in emergency room revealed a potassium concentration of 2.3 mmol/l. He had never used diuretics or hormonal therapy nor had history of vomiting or diarrhea. He had normal blood pressure and the blood gas analysis revealed metabolic alkalosis. On his ECG (electrocardiography), we found the prominent U wave. Despite his low concentration of serum potassium and cloride, the concentration of these electrolytes in urine were extremely high. We also found hipomagnesemia. The calcium concentration in serum was normal with slightly hypocalciuria. Even with aggressive oral and intravenous potassium suplementation, the patient remained hypokalemic. In cases when the etiology of hypokalemia is unclear, we should perform some investigations to confirm the diagnosis and give the proper treatment. In Gitelman's syndrome, where the defect in the distal tubule cannot be corrected, the treatment must be a life-long. Most patients require oral potassium and magnesium supplementation, since drug therapy is usually incompletely effective.

Intra-erythrocyte magnesium levels and their clinical implications in geriatric outpatients

OBJECTIVES

Magnesium deficiency has been implicated as a factor in numerous chronic diseases and previous studies suggest a greater prevalence of occult magnesium deficiency among older adults. Serum is the choice for the assessment of most analyses used in clinical medicine, although serum magnesium concentrations have been shown to be poor predictors of intracellular magnesium concentration. The aim of this study was to compare intracellular and extracellular magnesium concentrations in geriatric outpatients. Moreover, we examined whether a significant correlation between magnesium parameters and clinical outcome existed.

DESIGN

Cross-sectional study.

SETTING

Geriatric medicine outpatient clinic of a university hospital.

PARTICIPANTS

A total of 246 patients with a mean age of 71.9 ± 5.7 years were involved.

MEASUREMENTS

Intra-erythrocyte magnesium levels were analyzed with atomic absorption spectrophotometry.

RESULTS

Serum magnesium levels were within normal range in all patients, whereas intra-erythrocyte magnesium measurements were low in 57% of the patients. Increase in serum levels were together with just only a slightly increase in intra-erythrocyte measurements and the relationship was very weak. Intra-erythrocyte Mg levels were not significantly correlated with many laboratory or clinical parameters.

CONCLUSION

Our results confirm that intra-erythrocyte Mg does not correlate with serum levels and clinical parameters in geriatric outpatients, but further studies are needed to define the correlation.

Hypomagnesemia: an evidence-based approach to clinical cases

Hypomagnesemia is defined as a serum magnesium level less than 1.8 mg/dL (< 0.74 mmol/L). Hypomagnesemia may result from inadequate magnesium intake, increased gastrointestinal or renal losses, or redistribution from extracellular to intracellular space. Increased renal magnesium loss can result from genetic or acquired renal disorders. Most patients with hypomagnesemia are asymptomatic and symptoms usually do not arise until the serum magnesium concentration falls below 1.2 mg/dL. One of the most life-threatening effects of hypomagnesemia is ventricular arrhythmia. The first step to determine the likely cause of the hypomagnesemia is to measure fractional excretion of magnesium and urinary calcium-creatinine ratio. The renal response to magnesium deficiency due to increased gastrointestinal loss is to lower fractional excretion of magnesium to less than 2%. A fractional excretion above 2% in a subject with normal kidney function indicates renal magnesium wasting. Barter syndrome and loop diuretics which inhibit sodium chloride transport in the ascending loop of Henle are associated with hypokalemia, metabolic alkalosis, renal magnesium wasting, hypomagnesemia, and hypercalciuria. Gitelman syndrome and thiazide diuretics which inhibit sodium chloride cotransporter in the distal convoluted tubule are associated with hypokalemia, metabolic alkalosis, renal magnesium wasting, hypomagnesemia, and hypocalciuria. Familial renal magnesium wasting is associated with hypercalciuria, nephrocalcinosis, and nephrolithiasis. Asymptomatic patients should be treated with oral magnesium supplements. Parenteral magnesium should be reserved for symptomatic patients with severe magnesium deficiency (< 1.2 mg/dL). Establishment of adequate renal function is required before administering any magnesium supplementation.