Association of serum magnesium level change with in-hospital mortality

Initial Serum Magnesium Level Is Associated with Mortality Risk in Traumatic Brain Injury Patients

BACKGROUND

Electrolyte disorder is prevalent in traumatic brain injury (TBI) patients. This study is designed to explore the association between initial serum magnesium levels and mortality of TBI patients.

METHODS

TBI patients recorded in the Medical Information Mart for Intensive Care-III database were screened for this study. Logistic regression analysis was used to explore risk factors for mortality of included TBI patients. The restricted cubic spline (RCS) was applied to fit the correlation between initial serum magnesium level and mortality of TBI.

RESULTS

The 30-day mortality of included TBI patients was 17.0%. Patients with first-tertile and third-tertile serum magnesium levels had higher mortality than those of the second tertile. Univariate regression analysis showed that the serum magnesium level was not associated with mortality. Unadjusted RCS indicated the relationship between serum magnesium level mortality was U-shaped. After adjusting confounding effects, multivariate regression analysis presented that serum magnesium level was positively associated with mortality.

CONCLUSION

TBI patients with abnormally low or high levels of serum magnesium both have a higher incidence of mortality. At the same time, a higher initial serum magnesium level is independently associated with mortality in TBI patients. Physicians should pay attention to the clinical management of TBI patients, especially those with higher serum magnesium levels.

Machine Learning Consensus Clustering Approach for Hospitalized Patients with Dysmagnesemia

BACKGROUND

The objectives of this study were to classify patients with serum magnesium derangement on hospital admission into clusters using unsupervised machine learning approach and to evaluate the mortality risks among these distinct clusters.

METHODS

Consensus cluster analysis was performed based on demographic information, principal diagnoses, comorbidities, and laboratory data in hypomagnesemia (serum magnesium ≤ 1.6 mg/dL) and hypermagnesemia cohorts (serum magnesium ≥ 2.4 mg/dL). Each cluster's key features were determined using the standardized mean difference. The associations of the clusters with hospital mortality and one-year mortality were assessed.

RESULTS

In hypomagnesemia cohort (n = 13,320), consensus cluster analysis identified three clusters. Cluster 1 patients had the highest comorbidity burden and lowest serum magnesium. Cluster 2 patients had the youngest age, lowest comorbidity burden, and highest kidney function. Cluster 3 patients had the oldest age and lowest kidney function. Cluster 1 and cluster 3 were associated with higher hospital and one-year mortality compared to cluster 2. In hypermagnesemia cohort (n = 4671), the analysis identified two clusters. Compared to cluster 1, the key features of cluster 2 included older age, higher comorbidity burden, more hospital admissions primarily due to kidney disease, more acute kidney injury, and lower kidney function. Compared to cluster 1, cluster 2 was associated with higher hospital mortality and one-year mortality.

CONCLUSION

Our cluster analysis identified clinically distinct phenotypes with differing mortality risks in hospitalized patients with dysmagnesemia. Future studies are required to assess the application of this ML consensus clustering approach to care for hospitalized patients with dysmagnesemia.

Impact of serum magnesium levels at hospital discharge and one-year mortality

Background: We aimed to determine the optimal range of discharge serum magnesium in hospitalized patients by evaluating one-year mortality risk according to discharge serum magnesium.Methods: This was a single-center cohort study of hospitalized adult patients who survived until hospital discharge. We classified discharge serum magnesium, defined as the last serum magnesium within 48 hours of hospital discharge, into ≤1.6, 1.7-1.8, 1.9-2.0, 2.1-2.2, and ≥2.3 mg/dL. We assessed one-year mortality risk after hospital discharge based on discharge serum magnesium, using discharge magnesium of 2.1-2.2 mg/dL as the reference group.Results: Of 39,193 eligible patients, 8%, 23%, 34%, 23%, and 12% had a serum magnesium of ≤1.6, 1.7-1.8, 1.9-2.0, 2.1-2.2, and ≥2.3 mg/dL, respectively, at hospital discharge. After the adjustment for several confounders, discharge serum magnesium of ≤1.6, 1.7-1.8, and ≥2.3 mg/dL were associated with higher one-year mortality with hazard ratio of 1.35 (95% CI 1.21-1.50), 1.14 (95% CI 1.06-1.24), and 1.17 (95% CI 1.07-1.28), respectively, compared to discharge serum magnesium of 2.1-2.2 mg/dL. There was no significant difference in one-year mortality between patients with discharge serum magnesium of 1.9-2.0 and 2.1-2.2 mg/dL.Conclusion: The optimal range of serum magnesium at discharge was 1.9-2.2 mg/dL. Both hypomagnesemia and hypermagnesemia at discharge were associated with higher one-year mortality.

Hospital-acquired serum phosphate derangements and their associated in-hospital mortality

BACKGROUND

We aimed to report the incidence of hospital-acquired hypophosphataemia and hyperphosphataemia along with their associated in-hospital mortality.

METHODS

We included 15 869 adult patients hospitalised at a tertiary medical referral centre from January 2009 to December 2013, who had normal serum phosphate levels at admission and at least two serum phosphate measurements during their hospitalisation. The normal range of serum phosphate was defined as 2.5-4.2 mg/dL. In-hospital serum phosphate levels were categorised based on the occurrence of hospital-acquired hypophosphataemia and hyperphosphataemia. We analysed the association of hospital-acquired hypophosphataemia and hyperphosphataemia with in-hospital mortality using multivariable logistic regression.

RESULTS

Fifty-three per cent (n=8464) of the patients developed new serum phosphate derangements during their hospitalisation. The incidence of hospital-acquired hypophosphataemia and hyperphosphataemia was 35% and 27%, respectively. Hospital-acquired hypophosphataemia and hyperphosphataemia were associated with odds ratio (OR) of 1.56 and 2.60 for in-hospital mortality, respectively (p value<0.001 for both). Compared with patients with persistently normal in-hospital phosphate levels, patients with hospital-acquired hypophosphataemia only (OR 1.64), hospital-acquired hyperphosphataemia only (OR 2.74) and both hospital-acquired hypophosphataemia and hyperphosphataemia (ie, phosphate fluctuations; OR 4.00) were significantly associated with increased in-hospital mortality (all p values <0.001).

CONCLUSION

Hospital-acquired serum phosphate derangements affect approximately half of the hospitalised patients and are associated with increased in-hospital mortality rate.

Impact of serum phosphate changes on in-hospital mortality

Background

Fluctuations in serum phosphate levels increased mortality in end-stage renal disease patients. However, the impacts of serum phosphate changes in hospitalized patients remain unclear. This study aimed to test the hypothesis that serum phosphate changes during hospitalization were associated with in-hospital mortality.

Methods

We included all adult hospitalized patients from January 2009 to December 2013 that had at least two serum phosphate measurements during their hospitalization. We categorized in-hospital serum phosphate changes, defined as the absolute difference between the maximum and minimum serum phosphate, into 5 groups: 0–0.6, 0.7–1.3, 1.4–2.0, 2.1–2.7, ≥2.8 mg/dL. Using serum phosphate change group of 0–0.6 mg/dL as the reference group, the adjusted odds ratio of in-hospital mortality for various serum phosphate change groups was obtained by multivariable logistic regression analysis.

Results

A total of 28,149 patients were studied. The in-hospital mortality in patients with serum phosphate changes of 0–0.6, 0.7–1.3, 1.4–2.0, 2.1–2.7, ≥2.8 mg/dL was 1.5, 2.0, 3.1, 4.4, and 10.7%, respectively (p < 0.001). When adjusted for confounding factors, larger serum phosphate changes were associated with progressively increased in-hospital mortality with odds ratios of 1.35 (95% 1.04–1.74) in 0.7–1.3 mg/dL, 1.98 (95% CI 1.53–2.55) in 1.4–2.0 mg/dL, 2.68 (95% CI 2.07–3.48) in 2.1–2.7 mg/dL, and 5.04 (95% CI 3.94–6.45) in ≥2.8 mg/dL compared to serum phosphate change group of 0–0.6 mg/dL. A similar result was noted when we further adjusted for either the admission or mean serum phosphate during hospitalization.

Conclusion

Greater serum phosphate changes were progressively associated with increased in-hospital mortality.

Hospital-Acquired Dysmagnesemia and In-Hospital Mortality

Background and Objectives: This study aimed to report the incidence of hospital-acquired dysmagnesemia and its association with in-hospital mortality in adult general hospitalized patients. Materials and Methods: We studied 26,020 adult hospitalized patients from 2009 to 2013 who had normal admission serum magnesium levels and at least two serum magnesium measurements during hospitalization. The normal range of serum magnesium was 1.7-2.3 mg/dL. We categorized in-hospital serum magnesium levels based on the occurrence of hospital-acquired hypomagnesemia and/or hypermagnesemia. We assessed the association between hospital-acquired dysmagnesemia and in-hospital mortality using multivariable logistic regression. Results: 28% of patients developed hospital-acquired dysmagnesemia. Fifteen per cent had hospital-acquired hypomagnesemia only, 10% had hospital-acquired hypermagnesemia only, and 3% had both hospital-acquired hypomagnesemia and hypermagnesemia. Compared with patients with persistently normal serum magnesium levels in hospital, those with hospital-acquired hypomagnesemia only (OR 1.77; p < 0.001), hospital-acquired hypermagnesemia only (OR 2.31; p < 0.001), and both hospital-acquired hypomagnesemia and hypermagnesemia (OR 2.14; p < 0.001) were significantly associated with higher in-hospital mortality. Conclusions: Hospital-acquired dysmagnesemia affected approximately one-fourth of hospitalized patients. Hospital-acquired hypomagnesemia and hypermagnesemia were significantly associated with increased in-hospital mortality.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Impact of Changes in Serum Calcium Levels on In-Hospital Mortality

Background and objectives: Calcium concentration is strictly regulated at both the cellular and systemic level, and changes in serum calcium levels can alter various physiological functions in various organs. This study aimed to assess the association between changes in calcium levels during hospitalization and mortality. Materials and Methods: We searched our patient database to identify all adult patients admitted to our hospital from January 1st, 2009 to December 31st, 2013. Patients with ≥2 serum calcium measurements during the hospitalization were included. The serum calcium changes during the hospitalization, defined as the absolute difference between the maximum and the minimum calcium levels, were categorized into five groups: 0–0.4, 0.5–0.9, 1.0–1.4, 1.5–1.9, and ≥2.0 mg/dL. Multivariable logistic regression was performed to assess the independent association between calcium changes and in-hospital mortality, using the change in calcium category of 0–0.4 mg/dL as the reference group. Results: Of 9868 patients included in analysis, 540 (5.4%) died during hospitalization. The in-hospital mortality progressively increased with higher calcium changes, from 3.4% in the group of 0–0.4 mg/dL to 14.5% in the group of ≥2.0 mg/dL (p < 0.001). When adjusted for age, sex, race, principal diagnosis, comorbidity, kidney function, acute kidney injury, number of measurements of serum calcium, and hospital length of stay, the serum calcium changes of 1.0–1.4, 1.5–1.9, and ≥2.0 mg/dL were significantly associated with increased in-hospital mortality with odds ratio (OR) of 1.55 (95% confidence interval (CI) 1.15–2.10), 1.90 (95% CI 1.32–2.74), and 3.23 (95% CI 2.39–4.38), respectively. The association remained statistically significant when further adjusted for either the lowest or highest serum calcium. Conclusion: Larger serum calcium changes in hospitalized patients were progressively associated with increased in-hospital mortality.