Association between magnesium sulfate administration and mortality in critically ill patients with sepsis-associated acute kidney injury: a retrospective propensity score-matched cohort study

The effect of magnesium sulfate on long-term outcomes in patients with sepsis-associated acute kidney injury (SA-AKI) remains unknown. This study aimed to evaluate its association with long-term mortality in SA-AKI patients. We retrospectively analyzed data on patients with SA-AKI from the Medical Information Mart for Intensive Care-IV database. Magnesium sulfate administration after SA-AKI onset was defined as the exposure. Patients were matched 1:1 using propensity score matching (PSM). The primary endpoint was 1-year mortality; secondary endpoints included ICU mortality, in-hospital mortality, 28-day mortality, and major adverse kidney events within 30 days (MAKE30). Associations were assessed using multivariable analyses to calculate hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs). Among 16,156 patients, 13,672 received magnesium sulfate. After PSM, 4936 patients (2468 per group) were included. In the PSM cohort, 1-year mortality was lower in the magnesium sulfate group than in the non-use group (41.21% vs. 47.41%; P < 0.001). Magnesium sulfate administration was significantly associated with reduced 1-year mortality (HR, 0.77; 95% CI, 0.71–0.84; P < 0.001), consistent across all subgroup. MAKE30 incidence was also lower in the magnesium sulfate group (33.14% vs. 38.41%; P < 0.001), with a significant associated (OR, 0.83; 95% CI, 0.73–0.94; P = 0.004). Additionally, magnesium sulfate was associated with reduced ICU mortality, in-hospital mortality, and 28-day mortality. Sensitivity analysis performed in the original cohort also demonstrated similar results. Magnesium sulfate administration was associated with reduced long-term mortality in SA-AKI patients. These findings warrant confirmation through randomized controlled trials.