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.