Association of hyponatremia and outcomes in pulmonary hypertension.

Background: Hyponatremia is known to be an important marker and prognosticator in left-sided heart failure. However, less is known about the significance of hyponatremia in pulmonary hypertension, particularly in the absence of left ventricular dysfunction.
Methods and Results: We identified 635 patients with pulmonary hypertension and preserved ejection fraction who were normonatremic (n = 493) or hyponatremic (n = 142). End points were mortality and readmission at 1 year. Overall, 27% of all of the patients died within 1 year. Hyponatremia was significantly associated with an increased rate of 1-year mortality (hazard ratio [HR] 1.82, 95% confidence interval [CI] 1.27-2.61; P = .001) and trended toward an association with the composite of mortality and readmission (HR 1.25, 95% CI 0.97-1.62; P = .08). Additionally, the severity of hyponatremia was directly related to the rate of 1-year mortality (P < .001).
Conclusions: Hyponatremia is an indicator of poor prognosis in patients with echocardiographic evidence of pulmonary hypertension.
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