Magnesium levels and short- to medium-term cardiovascular events after percutaneous coronary intervention: a prospective cohort study

Magnesium (Mg) is an essential electrolyte that plays a critical role in cardiovascular physiology. Several studies have investigated the relationship between Mg levels and cardiovascular outcomes; however, the findings have been inconsistent. Therefore, this study aims to investigate the association between serum magnesium levels and short- to medium-term cardiovascular events in patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI). This prospective cohort study was conducted at the Isfahan Cardiovascular Research Institute, Isfahan, Iran, between October 2018 and September 2023, within the framework of the Persian Cardiovascular Disease Registry. Patients were followed for short-term (1-month and 6-month) and medium-term (12-month) major adverse cardiovascular events (MACE) after PCI and were categorized into three groups according to their admission serum magnesium levels: < 1.8 mg/dL, 1.8–2.2 mg/dL, and > 2.2 mg/dL. A total of 3,640 of the 5,300 patients with a confirmed diagnosis of AMI who underwent PCI met the eligibility criteria and were included in the final analysis. The mean age of the study population was 64.70 ± 12.07 years, and 80.3% of participants were male. At the 6-month follow-up, mortality was significantly higher among patients with serum Mg levels > 2.2 mg/dL (odds ratio [OR] = 1.45, P = 0.02). In contrast, at the 12-month follow-up, mortality was significantly higher among patients with serum Mg levels < 1.8 mg/dL (OR = 1.59, P < 0.01). The incidence of MACE was significantly higher among patients with serum Mg levels < 1.8 mg/dL at the 12-month follow-up (OR = 1.61, P < 0.01). Among patients with AMI undergoing PCI, both hypomagnesemia and hypermagnesemia were associated with adverse cardiovascular outcomes during follow-up. Hypomagnesemia was associated with an increased risk of medium-term mortality and major adverse cardiovascular events, whereas hypermagnesemia was associated with increased short-term mortality. These findings suggest a potential U-shaped association between serum magnesium levels and cardiovascular outcomes in this high-risk population. As this was an observational study, these findings reflect associations rather than causal relationships. Further prospective studies are warranted to confirm these associations before any clinical application is considered.