Prognostic importance of hyponatremia in acute ST-elevation myocardial infarction.
OBJECTIVE
To determine the prevalence and prognostic implications of hyponatremia in the setting of acute ST-elevation myocardial infarction.


METHODS
The study sample consisted of 1047 consecutive patients presenting with acute ST-elevation myocardial infarction. Plasma sodium concentrations were obtained on admission and at 24, 48, and 72 hours thereafter. Infarct size was determined by echocardiographic examination that was performed on day 2 or 3 of hospitalization.


RESULTS
Hyponatremia, defined as a plasma sodium level <135 mmol/L (<135 mEq/L), was present on admission in 131 patients (12.5%) and developed during the first 72 hours of hospitalization in 208 patients (19.9%). Plasma sodium levels decreased to < or = 130 mmol/L in 45 patients (4.3%). In a multivariate logistic regression analysis, hyponatremia was independently associated with 30-day mortality. The risk of 30-day mortality associated with hyponatremia on admission (odds ratio [OR] = 2.0; 95% confidence interval [CI]: 1.0 to 3.9; P = 0.04) was similar to that of hyponatremia developing after admission (OR = 2.4; 95% CI: 1.5 to 4.2; P = 0.002). The risk of 30-day mortality increased with the severity of hyponatremia, with an odds ratio of 2.1 in patients with sodium levels between 130 and 134 mmol/L (95% CI: 1.2 to 3.5; P = 0.007) and 3.4 in those with levels <130 mmol/L (95% CI: 1.5 to 7.8; P = 0.002).


CONCLUSIONS
Hyponatremia on admission or early development of hyponatremia in patients with acute ST-elevation myocardial infarction is an independent predictor of 30-day mortality, and prognosis worsens with the severity of hyponatremia. Further studies are required to determine if plasma sodium levels may serve as a simple marker to identify patients at high risk.
Department of Cardiology, Rambam Medical Center, Haifa, Israel.
Alexander
A
Goldberg
Haim
H
Hammerman
Sirouch
S
Petcherski
Alexander
A
Zdorovyak
Sergey
S
Yalonetsky
Michael
M
Kapeliovich
Yoram
Y
Agmon
Walter
W
Markiewicz
Doron
D
Aronson
D000368:Aged; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000502:physiology; D003402:Creatine Kinase / Q000097:blood; D005260:Female; D006329:Heart Conduction System / Q000378:metabolism / Q000473:pathology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007010:Hyponatremia / Q000097:blood / Q000175:diagnosis* / Q000401:mortality; D007557:Israel / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis* / Q000401:mortality; D011237:Predictive Value of Tests; D015995:Prevalence; D011379:Prognosis; D018570:Risk Assessment; D012964:Sodium / Q000097:blood; D013223:Statistics as Topic; D013318:Stroke Volume / Q000502:physiology; D016019:Survival Analysis
D015415:Biomarkers; D001786:Blood Glucose; D012964:Sodium; D003402:Creatine Kinase