Early Magnesium Sulfate Administration and Mortality in Critically Ill Patients with Pneumonia: A Retrospective Analysis of the MIMIC-IV Database

BackgroundDisturbances in magnesium homeostasis and magnesium supplementation are common in critical illness; however, the association between early intravenous magnesium sulfate administration and clinical outcomes in critically ill patients with pneumonia remains unclear.MethodsThis retrospective observational cohort study used data from the Medical Information Mart for Intensive Care IV (version 3.1) database and included critically ill patients admitted to the intensive care unit (ICU) with pneumonia. Patients were classified according to early exposure to intravenous magnesium sulfate, defined as administration from 6 h before to 24 h after ICU admission, or no exposure during this period. The primary outcome was 30-day all-cause mortality, with secondary outcomes including 60-day and 90-day mortality. Associations were evaluated using multivariable Cox proportional hazards models, with prespecified subgroup, interaction, and sensitivity analyses, including propensity score matching.ResultsAmong 9203 eligible patients, 2975 (32.3%) received early intravenous magnesium sulfate. Magnesium sulfate administration was associated with lower 30-day mortality after multivariable adjustment (adjusted hazard ratio [aHR] 0.84; 95% confidence interval [CI] 0.76-0.94; p = .002). Similar associations were observed for 60-day mortality (aHR 0.86; 95% CI 0.78-0.95; p = .002) and 90-day mortality (aHR 0.87; 95% CI 0.80-0.96; p = .004). Subgroup analysis identified a significant interaction for sepsis status (p for interaction = .007). In a propensity score-matched cohort, magnesium sulfate administration remained associated with lower 30-day mortality (aHR 0.85; 95% CI 0.74-0.96; p = .012).ConclusionsIn critically ill patients with pneumonia, early intravenous magnesium sulfate administration was associated with lower mortality. These findings are hypothesis-generating and suggest the need for prospective studies to clarify causality and define optimal dosing and duration of magnesium supplementation in this population.