Relationship between hyponatremia and in-hospital outcomes in Chinese patients with ST-elevation myocardial infarction

Abstract

Objective This study was investigated to determine the relationship between hyponatremia and in-hospital outcomes in Chinese patients with ST-elevation myocardial infarction. Methods Plasma sodium concentration was obtained in all patients on admission and analyzed as hyponatremia versus normalnatremia. The relationships between hyponatremia and in-hospital mortality as well as heart failure were assessed. Results Of 1,620 patients, 212 (13.1%) patients had hyponatremia on presentation (sodium <135 mmol/L). Patients with hyponatremia had higher rates of in-hospital mortality (13.7% vs. 7.3%, p=0.002) and heart failure (30.2% vs. 18%, p<0.001). Patients with a sodium level of <130 mmol/L had an adverse event rate of 22.9% versus 11.0% in patients with a sodium level of 130 to 135 mmol/L (p=0.034). In multivariate logistic regression, hyponatremia was independently correlated with in-hospital mortality (OR: 1.77, 95% CI: 1.02- 3.06, p=0.042) and heart failure (OR: 1.61, 95% CI: 1.06-2.43, p=0.025). Conclusion Hyponatremia is independently associated with in-hospital adverse outcomes in Chinese patients with acute ST-elevation myocardial infarction, and the risk of in-hospital mortality was increased with the severity of hyponatremia. © 2011 The Japanese Society of Internal Medicine.