Association between short-term changes in serum magnesium and in-hospital mortality following acute myocardial infarction: a cohort study based on the MIMIC database.

The association between short-term changes in serum magnesium level and risk of in-hospital mortality was investigated in patients with acute myocardial infarction (AMI). In this retrospective cohort study, data of 2,716 patients with AMI were extracted from the Medical Information Mart for Intensive Care (MIMIC-III and MIMIC-IV) database for 2001-2012. Univariate and multivariate Cox proportional hazards models were used to explore the association between serum magnesium level and short-term change and in-hospital mortality in patients with AMI. In addition, subgroups according to age, gender, Sequential Organ Failure Assessment (SOFA) score, and Simplified Acute Physiology Score (SAPS-II) were also analysed. In total, 504 (18.6%) patients died in hospital. After adjusting for covariates, all AMI patients with high magnesium levels at ICU admission (HR=1.03, 95% CI: 0.83-1.27) or 48 hours after ICU admission (all p<0.05), or those demonstrating a change in magnesium level within the first 48 hours of ICU stay (all p<0.05) were shown to have a high risk of in-hospital mortality. Moreover, this correlation was retained irrespective of age, gender, SOFA score, and SAPS-II (all p<0.05). Serum magnesium levels at different time points after ICU admission and change in serum magnesium level during the first 48 hours were associated with in-hospital mortality in patients with AMI, indicating that clinical attention should be paid to short-term changes in serum magnesium levels regarding treatment adjustment, which may further reduce the risk of mortality.