Abstract
Background
Hyponatremia is the most common electrolyte abnormality in hospitalized patients and
is associated with adverse outcomes, but its prevalence and significance in the general
US population is unknown. Our aims were to determine the prevalence of hyponatremia
and its association with mortality in the population.
Methods
We performed a population-based, cross-sectional study of 14,697 adults aged ≥18 years
who participated in the nationally representative National Health and Nutrition Examination
Survey for 1999-2004. By using measurements of serum sodium corrected for dilutional
effect of hyperglycemia, we determined the association of hyponatremia with patient
characteristics, comorbidities, and prescription medications, and performed unadjusted
and adjusted Cox proportional hazards regression to find the association of hyponatremia
with all-cause mortality.
Results
We provide the first estimate of the prevalence of hyponatremia in the US population,
which in our weighted analysis was 1.72%. Prevalence of hyponatremia was significantly
higher in women (2.09%, P = .004) and increased with age. Hyponatremia was more common in subjects with hypertension,
diabetes, coronary artery disease, stroke, chronic obstructive pulmonary disease,
cancer, and psychiatric disorders, and less common in those with no comorbidities
(1.04%, P < .001). There was a significant risk of death associated with hyponatremia in unadjusted
(hazard ratio [HR], 3.61; P < .001) and adjusted Cox models controlling for demographics, smoking, comorbidities,
and insurance status (HR, 2.43; P < .001). There was a U-shaped relationship between serum sodium and HR for mortality.
Conclusions
Our findings suggest that hyponatremia is a predictor of mortality in the general
population independently of age, gender, and comorbid conditions.
Keywords
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Article info
Footnotes
Funding: This work was supported in part by Health Resources and Services Administration Contract 234–2005-370011C and National Institute of Diabetes and Digestive and Kidney Diseases Grant T35 DK093430.
Conflict of Interest: None.
Authorship: All authors had access to the data and played a role in writing this manuscript.
Identification
Copyright
© 2013 Elsevier Inc. Published by Elsevier Inc. All rights reserved.
