Outcomes of correcting hyponatremia in patients with myocardial infarction
Hyponatremia has significant prognostic implications in patients with heart, failure. However, little data are available regarding its significance in patients presenting with myocardial infarction. In addition, it is not known if correction of hyponatremia impacts outcomes in these patients. The aim of this study was to evaluate the prognostic value of hyponatremia in patients with myocardial infarction and the effect of its correction on all-cause mortality.
Patients with the discharge diagnosis of myocardial infarction at our institution between 2000 and 2010 with serum sodium levels measured within 24 h of admission were included in this retrospective analysis. Multivariate analysis was used to determine the predictors of all-cause mortality. Cox proportional hazard model was applied to determine the adjusted survival.
A total of 11,562 patients (67.15 ± 14.6 years, males 56.3 %) were included in the analysis. There were a total of 1,535 (13.3 %) deaths within mean follow-up duration of 5.5 ± 3.3 years. There were 425 (27.9 %) deaths in patients with corrected hyponatremia and 155 (55.3 %) deaths in persistent hyponatremia patients. Multivariate analysis indicated that corrected hyponatremia and persistent hyponatremia were independent predictors of all cause mortality (p < 0.0001). When analyzing short-term (30 days) and long-term mortality, corrected hyponatremia group did not have associated long term mortality. Various methods to correct hyponatremia were also analyzed and use of vaptans was associated with decrease in mortality in patients with hyponatremia from 115 to 125 (HR 0.45; 95 % CI 0.26–0.78, p = 0.005).
Our analysis showed that corrected and persistent hyponatremia in patients presenting with myocardial infarction is a predictor of all-cause mortality, major adverse cardiac events and heart failure related 30 day rehospitalization. In certain cases, correction of hyponatremia may actually improve survival of the patients.