Serum Magnesium Is Associated with Long-Term Survival of Non-ST-Elevation Myocardial Infarction Patients

Low serum magnesium (sMg) is associated with cardiovascular risk factors and atherosclerotic disease.

To evaluate the association between sMg levels on admission and clinical outcomes in hospitalized non-ST-elevation myocardial infarction (NSTEMI) patients.

A retrospective analysis of all patients admitted to a single tertiary center with a primary diagnosis of NSTEMI. Patients with advanced chronic kidney disease were excluded. Clinical data were collected and compared between lower sMg quartile patients (Q1; sMg < 1.9 mg/dL) and all other patients (Q2-Q4; sMg ≥ 1.9 mg/dL).

The study cohort included 4552 patients (70% male, median age 69 [IQR 59-79]) who were followed for a median of 4.4 (IQR 2.4-6.6) years. The median sMg level in the low sMg group was 1.7 (1.6-1.8) and 2.0 (2.0-2.2) mg/dL in the normal/high sMg group. The low sMg group was older (mean of 72 vs. 67 years), less likely to be male (64% vs. 72%), and had higher rates of comorbidities, including diabetes, hypertension, and atrial fibrillation (59% vs. 29%, 92% vs. 85%, and 6% vs. 5%; p < 0.05 for all). Kaplan-Meier survival analysis demonstrated significantly higher cumulative death probability at 4 years in the low sMg group (34% vs. 22%; p log rank <0.001). In a multivariable analysis model adjusted for sex, significant comorbidities, coronary interventions during the hospitalization, and renal function, the low sMg group exhibited an independent 24% increased risk of death during follow up (95% CI 1.11-1.39; p < 0.001).

Low sMg is independently associated with higher risk of long-term mortality among patients recovering from an NSTEMI event.