Serum and cerebrospinal fluid magnesium levels, Glasgow Coma Scores, and in-hospital mortality in patients with acute stroke

Machine Learning for Predicting Risk and Prognosis of Acute Kidney Disease in Critically Ill Elderly Patients During Hospitalization: Internet-Based and Interpretable Model Study

BACKGROUND

Acute kidney disease (AKD) affects more than half of critically ill elderly patients with acute kidney injury (AKI), which leads to worse short-term outcomes.

OBJECTIVE

We aimed to establish 2 machine learning models to predict the risk and prognosis of AKD in the elderly and to deploy the models as online apps.

METHODS

Data on elderly patients with AKI (n=3542) and AKD (n=2661) from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database were used to develop 2 models for predicting the AKD risk and in-hospital mortality, respectively. Data collected from Xiangya Hospital of Central South University were for external validation. A bootstrap method was used for internal validation to obtain relatively stable results. We extracted the indicators within 24 hours of the first diagnosis of AKI and the fluctuation range of some indicators, namely delta (day 3 after AKI minus day 1), as features. Six machine learning algorithms were used for modeling; the area under the receiver operating characteristic curve (AUROC), decision curve analysis, and calibration curve for evaluating; Shapley additive explanation (SHAP) analysis for visually interpreting; and the Heroku platform for deploying the best-performing models as web-based apps.

RESULTS

For the model of predicting the risk of AKD in elderly patients with AKI during hospitalization, the Light Gradient Boosting Machine (LightGBM) showed the best overall performance in the training (AUROC=0.844, 95% CI 0.831-0.857), internal validation (AUROC=0.853, 95% CI 0.841-0.865), and external (AUROC=0.755, 95% CI 0.699-0.811) cohorts. In addition, LightGBM performed well for the AKD prognostic prediction in the training (AUROC=0.861, 95% CI 0.843-0.878), internal validation (AUROC=0.868, 95% CI 0.851-0.885), and external (AUROC=0.746, 95% CI 0.673-0.820) cohorts. The models deployed as online prediction apps allowed users to predict and provide feedback to submit new data for model iteration. In the importance ranking and correlation visualization of the model's top 10 influencing factors conducted based on the SHAP value, partial dependence plots revealed the optimal cutoff of some interventionable indicators. The top 5 factors predicting the risk of AKD were creatinine on day 3, sepsis, delta blood urea nitrogen (BUN), diastolic blood pressure (DBP), and heart rate, while the top 5 factors determining in-hospital mortality were age, BUN on day 1, vasopressor use, BUN on day 3, and partial pressure of carbon dioxide (PaCO2).

CONCLUSIONS

We developed and validated 2 online apps for predicting the risk of AKD and its prognostic mortality in elderly patients, respectively. The top 10 factors that influenced the AKD risk and mortality during hospitalization were identified and explained visually, which might provide useful applications for intelligent management and suggestions for future prospective research.

Frequency of Hypomagnesemia and Its Relationship With Severity Among Patients of Acute Ischemic Stroke Presenting to a Tertiary Care Hospital

Objective The objective of this study was to assess the prevalence of hypomagnesemia and its association with the severity of acute ischemic stroke (AIS) in patients presenting at a tertiary care hospital. Methodology A total of 100 patients with AIS were included in the study. Demographic data, including age, gender, and severity of stroke, were collected. Serum magnesium levels were measured at admission, and the severity of stroke was classified as mild, moderate, or severe based on clinical criteria. The presence of hypomagnesemia was defined as a serum magnesium level below 1.8 mg/dL determined within 72 hours of onset of stroke. Statistical analysis was performed to assess the association between hypomagnesemia, stroke severity, age, and gender. Results The mean age of the patients with standard deviation was 65.45 ± 11.8 years, with the majority (38, 38%) aged 60-74 years. There were 53 (53%) male and 47 (47%) female patients. Hypomagnesemia was found in 35 (35%) patients, with an average magnesium level of 1.93 mg/dL and a standard deviation of 0.37 at admission. There was no statistically significant difference in the distribution of stroke severity (P = 0.779; P = 0.406) or hypomagnesemia (P = 0.287; P = 0.591) based on gender or age group, respectively. Stratification based on stroke severity showed that 16 (39%) patients with mild stroke, 10 (31.3%) with moderate stroke, and 9 (33.3%) with severe stroke had hypomagnesemia. The correlation between stroke severity and hypomagnesemia was weak (r = 0.099). Further, among hypomagnesemia patients, the majority were females aged 60-74 years. Conclusions This study found a weak positive relationship between the severity of AIS and the presence of hypomagnesemia. However, no statistically significant association was observed between gender or age group and stroke severity or hypomagnesemia. These findings suggest that further research is needed to understand the role of hypomagnesemia in AIS and its potential implications for patient management.

Magnesium intake and all-cause mortality after stroke: a cohort study

BACKGROUND

Population-based studies have shown that adequate magnesium intake is associated with a lower risk of stroke and all-cause mortality. Whether adequate magnesium intake is important for reducing all-cause mortality risk after stroke remains unclear.

METHODS

We analyzed data from 917 patients with a self-reported history of stroke from the National Health and Nutrition Examination Survey (NHANES) 2007-2018. The total magnesium intake was calculated by summing the magnesium intake from dietary and dietary supplements, and then adjusting for total energy intake according to the nutrient density method. Mortality status was determined using public-use linked mortality files from 2019. Cox regression model and restricted cubic splines were used to explore the relationship between magnesium intake and all-cause mortality.

RESULTS

The average total magnesium intake across all patients was 251.0 (184.5-336.5) mg/d, and 321 (70.2%) males and 339 (73.7%) females had insufficient magnesium intake. During a median follow-up period of 5.3 years, 277 deaths occurred. After fully adjusting for confounding factors, total magnesium intake levels were inversely associated with all-cause mortality risk (HR per 1-mg/(100 kcal*d) increase, 0.97; 95% CI, 0.94-1.00; p = 0.017). Participants with the highest quartile of total magnesium intake (≥ 18.5 mg/(100 kcal*d)) had a 40% reduction in all-cause mortality risk compared to those with the lowest quartile (≤ 12.0 mg/(100 kcal*d)) (HR, 0.60; 95% CI, 0.38-0.94; p = 0.024). Stratified analyses showed that this inverse association was statistically significant in those who were older, female, without hypertension, and had smoking, normal renal function, and adequate energy intake. Dietary magnesium intake alone might be not related to all-cause mortality.

CONCLUSIONS

Stroke survivors who consumed adequate amounts of magnesium from diet and supplements had a lower risk of all-cause mortality.

Low serum magnesium is associated with poor functional outcome in acute ischemic stroke or transient ischemic attack patients

AIM

The association between magnesium and outcomes after stroke is uncertain. We aimed to investigate the association of serum magnesium with all-cause mortality and poor functional outcome.

METHODS

We included patients with acute ischemic stroke (AIS) or transient ischemic attack (TIA) from the China National Stroke Registry III. We used Cox proportional hazards model for all-cause mortality and logistic regression model for poor functional outcome (modified Rankin Scale [mRS] 2-6/3-6) to examine the relationships.

RESULTS

Among the 6483 patients, the median (interquartile range) magnesium was 0.87 (0.80-0.93) mmol/L. Patients in the first quartile had a higher risk of mRS score 3-6/2-6 at 3 months (adjusted odds ratio [OR]: 1.30; 95% confidence interval [CI]: 1.02, 1.64; adjusted OR: 1.29; 95% CI: 1.04-1.59) compared with those in the fourth quartile. Similar results were found for mRS score 26 at 1 year. The age- and sex-adjusted hazard ratio (HR) with 95% CI in first quartile magnesium was 1.40 (1.02-1.93) for all-cause mortality within 1 year, but became insignificant (HR: 1.03; 95% CI: 0.71-1.50) after adjusting for potential variables.

CONCLUSIONS

Low serum magnesium was associated with a high risk of poor functional outcome in patients with AIS or TIA.

Current status and outlook of biodegradable metals in neuroscience and their potential applications as cerebral vascular stent materials

Over the past two decades, biodegradable metals (BMs) have emerged as promising materials to fabricate temporary biomedical devices, with the purpose of avoiding potential side effects of permanent implants. In this review, we first surveyed the current status of BMs in neuroscience, and briefly summarized the representative stents for treating vascular stenosis. Then, inspired by the convincing clinical evidence on the in vivo safety of Mg alloys as cardiovascular stents, we analyzed the possibility of producing biodegradable cerebrovascular Mg alloy stents for treating ischemic stroke. For these novel applications, some key factors should also be considered in designing BM brain stents, including the anatomic features of the cerebral vasculature, hemodynamic influences, neuro-cytocompatibility and selection of alloying elements. This work may provide insights into the future design and fabrication of BM neurological devices, especially for brain stents.

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The current status of the application of biodegradable metals (BM) in neuroscience was presented.

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We analyzed the possibility of producing biodegradable cerebrovascular Mg alloy stents for ischemic stroke treatment.

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Key factors in designing BM brain stents were discussed.

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This work may provide insights into the future design and fabrication of BM neurological devices, especially for brain stents.

Epileptiform activity in mouse hippocampal slices induced by moderate changes in extracellular Mg2+, Ca2+, and K. BMC Neurosci 2021;22:46. [PMID: 34301200 PMCID: PMC8305515 DOI: 10.1186/s12868-021-00650-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

BACKGROUND

Rodent brain slices-particularly hippocampal slices-are widely used in experimental investigations of epileptiform activity. Oxygenated artificial cerebrospinal fluid (ACSF) is used to maintain slices in vitro. Physiological or standard ACSF containing 3-3.5 mM K⁺, 1-2 mM Mg²⁺, and 1-3 mM Ca²⁺ generally does not induce population epileptiform activity, which can be induced by ACSF with high K⁺ (8-10 mM), low Mg²⁺, or low Ca²⁺ alone or in combination. While low-Mg²⁺ ACSF without intentionally added Mg salt but with contaminating Mg²⁺ (≤ 50-80 µM) from other salts can induce robust epileptiform activity in slices, it is unclear whether such epileptiform activity can be achieved using ACSF with moderately decreased Mg²⁺. To explore this issue, we examined the effects of moderately modified (m)ACSF with 0.8 mM Mg²⁺, 1.3 mM Ca²⁺, and 5.7 mM K⁺ on induction of epileptiform discharges in mouse hippocampal slices.

RESULTS

Hippocampal slices were prepared from young (21-28 days old), middle-aged (13-14 months old), and aged (24-26 months old) C57/BL6 mice. Conventional thin (0.4 mm) and thick (0.6 mm) slices were obtained using a vibratome and pretreated with mACSF at 35-36 °C for 1 h prior to recordings. During perfusion with mACSF at 35-36 °C, spontaneous or self-sustained epileptiform field potentials following high-frequency stimulation were frequently recorded in slices pretreated with mACSF but not in those without the pretreatment. Seizure-like ictal discharges were more common in thick slices than in thin slices.

CONCLUSIONS

Prolonged exposure to mACSF by pretreatment and subsequent perfusion can induce epileptiform field potentials in mouse hippocampal slices.

Neuroprotective effect of magnesium supplementation on cerebral ischemic diseases

Ischemic encephalopathy is associated with a high mortality and rate of disability. The most common type of ischemic encephalopathy, ischemic stroke, is the second leading cause of death in the world. At present, the main treatment for ischemic stroke is to reopen blocked blood vessels. However, despite revascularization, many patients are not able to achieve good functional results. At the same time, the strict time window (<4.5 h) of thrombolytic therapy limits clinical application. Therefore, it is important to explore effective neuroprotective drugs for the treatment of ischemic stroke. Magnesium is a natural calcium antagonist, which exerts neuroprotective effects through various mechanisms. However, while most basic studies have shown that magnesium supplementation can help treat cerebral ischemia, intravenous magnesium supplementation in large clinical trials has failed to improve prognosis of ischemic patients. Therefore, we review the basic and clinical studies of magnesium supplementation for cerebral ischemia. According to the route of administration, treatment can be divided into intraperitoneal magnesium supplementation, intravenous magnesium supplementation, arterial magnesium supplementation and intracranial magnesium supplementation. We also summarized the potential influencing factors of magnesium ion intervention in cerebral ischemia injury. Finally, in combination with influencing factors derived from basic research, this article proposes three future research directions, including magnesium supplementation into the circulatory system combined with magnesium supplementation in the lateral ventricle, magnesium supplementation in the lateral ventricle combined with hypothermia therapy, and lateral ventricle magnesium supplementation combined with intracarotid magnesium supplementation combined with selective hypothermia.

Prognostic Significance of Serum Magnesium in Acute Intracerebral Hemorrhage Patients

Background:

Experimental animal model studies have shown neuroprotective properties of magnesium. We assessed the relationship between admission magnesium and admission stroke severity and 3-month clinical outcomes in patients with acute intracerebral hemorrhage (ICH).

Methods:

The present study included 323 patients with acute ICH who were prospectively identified. Demographic characteristics, lifestyle risk factors, National Institute of Health Stroke Scale (NIHSS) score, hematoma volumes, and other clinical features were recorded at baseline for all participants. Patients were divided into three groups based on the admission magnesium levels (T1: <0.84; T2: 0.84-0.91; T3: =0.91 mmol/L). Clinical outcomes were death, poor functional outcome (defined by modified rankin ccale [mRS] scores 3-6) at 3 months.

Results:

After 3-month follow-up, 40 (12.4%) all-cause mortality and 132 (40.9%) poor functional outcome were documented. Median NIHSS scores for each tertile (T1 to T3) were 8.0, 5.5, and 6.0, and median hematoma volumes were 10.0, 8.05, and 12.4 ml, respectively. There was no significant association between baseline NIHSS scores (P=0.176) and hematoma volumes (P=0.442) in T3 and T1 in multivariable linear regression models. Compared with the patients in T1, those in T3 were associated with less frequency of all-cause mortality [adjusted odds ratio (OR), 0.10; 95% confidence interval (CI), 0.02-0.54; P-trend=0.010] but not poor functional outcome (adjusted OR, 1.80; 95%CI, 0.71-4.56; P-trend=0.227) after adjustment for potential confounders.

Conclusion:

Elevated admission serum magnesium level is associated with lower odds of mortality but not poor functional outcome at 3 months in patients with acute ICH.

Magnesium: Pathophysiological mechanisms and potential therapeutic roles in intracerebral hemorrhage

Intracerebral hemorrhage (ICH) remains the second-most common form of stroke with high morbidity and mortality. ICH can be divided into two pathophysiological stages: an acute primary phase, including hematoma volume expansion, and a subacute secondary phase consisting of blood-brain barrier disruption and perihematomal edema expansion. To date, all major trials for ICH have targeted the primary phase with therapies designed to reduce hematoma expansion through blood pressure control, surgical evacuation, and hemostasis. However, none of these trials has resulted in improved clinical outcomes. Magnesium is a ubiquitous element that also plays roles in vasodilation, hemostasis, and blood-brain barrier preservation. Animal models have highlighted potential therapeutic roles for magnesium in neurological diseases specifically targeting these pathophysiological mechanisms. Retrospective studies have also demonstrated inverse associations between admission magnesium levels and hematoma volume, hematoma expansion, and clinical outcome in patients with ICH. These associations, coupled with the multifactorial role of magnesium that targets both primary and secondary phases of ICH, suggest that magnesium may be a viable target of study in future ICH studies.

Admission Low Magnesium Level Is Associated with In-Hospital Mortality in Acute Ischemic Stroke Patients

BACKGROUND

Low magnesium levels are associated with an elevated risk of stroke. In this study, we investigated the association between magnesium levels on hospital admission and in-hospital mortality in acute ischemic stroke (AIS) patients.

METHODS

A total of 2,485 AIS patients, enrolled from December 2013 to May 2014 across 22 hospitals in Suzhou city, were included in this study. The patients were divided into 4 groups according to their level of admission magnesium: Q1 (<0.82 mmol/L), Q2 (0.82-0.89 mmol/L), Q3 (0.89-0.98 mmol/L), and Q4 (≥0.98 mmol/L). Cox proportional hazard model was used to estimate the effect of magnesium on all-cause in-hospital mortality in AIS patients.

RESULTS

During hospitalization, 92 patients (3.7%) died from all causes. The lowest serum magnesium level (Q1) was associated with a 2.66-fold increase in the risk of in-hospital mortality in comparison to Q4 (hazard ratio [HR] 2.66; 95% CI 1.55-4.56; p-trend < 0.001). After adjusting for age, sex, time from onset to hospital admission, baseline National Institutes of Health Stroke Scale score, and other potential covariates, HR for Q1 was 2.03 (95% CI 1.11-3.70; p-trend = 0.014). Sensitivity and subgroup analyses further confirmed a significant association between lower magnesium levels and a high risk of in-hospital mortality.

CONCLUSIONS

Decreased serum magnesium levels at admission were independently associated with in-hospital mortality in AIS patients.

Plasma magnesium and risk of ischemic stroke among women

BACKGROUND AND PURPOSE

Lower plasma magnesium levels may be associated with higher blood pressure and endothelial dysfunction, but sparse prospective data are available for stroke.

METHODS

Among 32,826 participants in the Nurses' Health Study who provided blood samples in 1989 to 1990, incident ischemic strokes were identified and confirmed by medical records through 2006. We conducted a nested case-control analysis of 459 cases, matched 1:1 to controls on age, race/ethnicity, smoking status, date of blood draw, fasting status, menopausal status, and hormone use. We used conditional logistic regression models to estimate the multivariable adjusted association of plasma magnesium and the risk of ischemic stroke and ischemic stroke subtypes.

RESULTS

Median magnesium levels did not differ between ischemic stroke cases and controls (median, 0.86 mmol/L for both; P=0.14). Conditional on matching factors, women in the lowest magnesium quintile had a relative risk of 1.34 (95% confidence interval, 0.86-2.10; P trend=0.13) for total ischemic stroke compared with women in the highest quintile. Additional adjustment for risk factors and confounders did not substantially alter the risk estimates for total ischemic stroke. Women with magnesium levels<0.82 mmol/L had significantly greater risk of total ischemic stroke (multivariable relative risk, 1.57; 95% confidence interval, 1.09-2.27; P=0.01) and thrombotic stroke (multivariable relative risk, 1.66; 95% confidence interval, 1.03-2.65; P=0.03) compared with women with magnesium levels≥0.82 mmol/L. No significant effect modification was observed by age, body mass index, hypertension, or diabetes mellitus.

CONCLUSIONS

Lower plasma magnesium levels may contribute to higher risk of ischemic stroke among women.

Magnesium: potential roles in neurovascular disease

OBJECTIVE

Magnesium therapy has been studied extensively in pre-clinical and clinical trials in multiple organ systems. Cerebrovascular diseases may benefit from its neuroprotective properties. This review summarizes current studies of magnesium in a wide range of neurovascular diseases.

METHODS

We searched relevant terms in the National Library of Medicine PubMed database and selected research including basic science, translational reports, meta-analyses, and clinical studies.

RESULTS

Studies examining magnesium administration in ischemic stroke have failed to show any benefit in clinical outcome. Data on magnesium for intracerebral hemorrhage (ICH) are limited. Preliminary investigations in subarachnoid hemorrhage (SAH) were promising, but definitive studies did not reveal differences in clinical outcome between magnesium and placebo-treated groups. Studies examining magnesium administration in global ischemia following cardiac arrest suggest a trend toward improved clinical outcome. The strongest evidence for clinically relevant neuroprotection following magnesium administration derives from studies of pre-term infants and patients undergoing cardiac bypass and carotid endarterectomy procedures. Magnesium was found to have an excellent safety profile across all investigations.

CONCLUSION

Magnesium is easy to administer and possesses a favorable safety profile. Its utility as a neuroprotectant in cardiac surgery, carotid endarterectomy, and pre-term infant hypoxia remain promising. Value as a therapeutic agent in ischemic stroke, ICH, and SAH is unclear and appears to be limited by late administration. Ongoing clinical trials assessing magnesium administration in the first hours following symptom onset may help clarify the role of magnesium therapy in these disease processes.