The prognosis of hyponatremia at hospital admission

To assess the risk of mortality in patients with hyponatremia at the time of hospital admission, the authors studied data for 13,979 patients admitted over a 46-month period. Of the 763 (4%) admitted with hyponatremia, 757 (99%) were matched by age, gender, and admitting date with normonatremic control patients. Hyponatremic patients were more than seven times as likely to die in the hospital than the control patients, and they were more than twice as likely to die after discharge (p<0.0001 for both). This relationship with in- and outpatient mortality held when controlling for the diagnoses found more often in the hyponatremic patients. Hyponatremia appears to be an indicator of increased risk of death regardless of the disease with which it is associated. Received from the Divisions of General Internal Medicine and Endocrinology, Department of Medicine, Indiana University School of Medicine, and the Regenstrief Institute for Health Care, Indianapolis, Indiana. Supported in part by the National Center for Health Services Research, DHHS, under research grant number HS-04996.