Association of Intravenous Magnesium Sulfate With Mortality in Patients With Myocardial Infarction: A Retrospective Cohort Study.

backgroundIn recent years, studies have increasingly focused on the role of magnesium ions in cardiovascular disease; however, its clinical significance in patients with acute myocardial infarction remains controversial. This study aimed to evaluate the association of intravenous magnesium sulfate administration on 28-day all-cause mortality among patients with acute myocardial infarction across different time windows of treatment initiation.

methodsThis retrospective observational cohort study analyzed data from patients diagnosed with acute type 1 myocardial infarction using the Medical Information Marketplace in Intensive Care (MIMIC)-IV database. Patients were categorized into five groups based on the timing of magnesium sulfate initiation: Q1 (not received), Q2 (≤ 2 h), Q3 (2-6 h), Q4 (6-12 h), and Q5 (≥ 12 h). The primary outcome was 28-day all-cause mortality, while the secondary outcome was one-year all-cause mortality. Adjusted Kaplan-Meier survival curve analysis and log-rank test were used to evaluate the association between intravenous magnesium sulfate administration and long-term mortality risk. Landmark analysis was performed to assess both short-term and long-term connections. Restricted mean survival time (RMST) was calculated as part of the sensitivity analysis to further investigate treatment correlations.

resultsA total of 4610 patients were included in this retrospective observational cohort study, with an overall 28-day all-cause mortality rate of 18.5%. Adjusted Kaplan-Meier survival analysis revealed that magnesium sulfate administration was significantly associated with reduced one-year all-cause mortality Lower mortality risks were observed across all treatment time groups. Landmark analysis showed a significantly higher association before the 28-day mark (P < 0.001). RMST analysis confirmed the consistency and robustness of these findings.

conclusionsThis single-center observational study in the PCI era demonstrates an association between intravenous magnesium sulfate and reduced mortality in patients with acute myocardial infarction, but it cannot establish causality because of potential residual and unmeasured confounding and other inherent biases. Future, well-designed randomized controlled trials are needed to determine whether magnesium sulfate truly improves outcomes in this population.