IN THE NEWS- Hyponatremia and Mortality( its the underlying cause that is more important)

Severe hyponatremia (<120 mEq/L) in hospitalized patients has a high mortality rate. This new study in CJASN 2011 issue online reviews this in a retrospective fashion. Medical records of 53 patients who died after developing Na <120 mEq/L before or after admission and of 32 patients who survived after developing Na <110 mEq/L were reviewed. Mortality rates tended to increase as the Na fell from 134 to 120 mEq/L.
Interestingly, Less than Na of 120 mEq/L, the trend reversed, such that the mortality rate progressively decreased as Na fell. More than two thirds of patients who died after Na <120mEq/L had at least two additional acute severe progressive illnesses, most commonly sepsis and multiorgan failure.  Most patients who survived with Na <110 mEq/L had medication-induced hyponatremia. The authors conclude that the nature of underlying illness rather than the severity of hyponatremia best explains mortality associated with hyponatremia. Neurologic complications from hyponatremia are uncommon among patients who die with hyponatremia.
Ref:
http://www.ncbi.nlm.nih.gov/pubmed/21441132