High serum magnesium level is associated with increased mortality in patients with sepsis: an international, multicenter retrospective study

Magnesium imbalances commonly exist in septic patients. However, the association of serum magnesium levels with mortality in septic patients remains uncertain. Herein, we elucidated the association between serum magnesium and all-cause mortality in septic patients from American and Chinese cohorts by analyzing data from 9099 patients in the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database and 1727 patients from a university-affiliated hospital’ intensive care unit in China. Patients in both cohorts were categorized into five groups based on serum magnesium quintiles from the MIMIC-IV dataset. Patients with higher serum magnesium levels exhibited an increased risk of 28-day mortality in both cohorts. The restricted cubic spline (RCS) curves revealed a progressively elevated risk of 28-day mortality with increasing serum magnesium in MIMIC-IV cohort, while a J-shaped correlation was observed in institutional cohort. Our findings have validated the association between high serum magnesium and high mortality in sepsis across different races and medical conditions. Serum magnesium levels might be useful in identifying septic patients at higher mortality risk.