By: James Pitt  May. 08, 2018
Hyponatremia is an unusually low level of sodium in the blood. Normal sodium levels are 135 to 145 mEq/L. A 2015 review in Journal of Intensive Care Medicine found that hyponatremia is the most common electrolyte abnormality in hospitalized patients, frequently encountered in intensive care units (ICUs).
There are notorious cases of patient deaths from hyponatremia after drinking too much water and diluting blood sodium, particularly in high-intensity exercise. But hyponatremia has many possible causes. As Dexur has previously reported, heart failure may cause hyponatremia. This occurs when the renin angiotensin system interprets reduced cardiac output as reduced blood volume, and retains water (thus reducing sodium concentration) to compensate.
To investigate correlations between heart failure and hyponatremia conditions and intensive unit (ICU) stays, Dexur analysts examined 2013-2016 CMS inpatient claims data from Maryland hospitals with over 5,000 patients per year. Patients with DRG 291 (heart failure and shock with major complications and comorbidities) were the population of interest.
On average, DRG 291 patients with hyponatremia had higher odds of an ICU stay than DRG 291 patients without hyponatremia. The strength of this relationship varied widely. At Greater Baltimore Medical Center, the odds ratio is incalculable because all DRG 291 patients with hyponatremia had an ICU stay. Caroll Hospital (Westminster, MD) had an odds ratio of 2.44, while Sinai Hospital (Baltimore, MD) had an odds ratio of 2.36. At the lower end, there were two hospitals where patients with hyponatremia had lower odds of an ICU stay than other DRG 291 patients. Holy Cross Hospital (Silver Spring, MD) had an odds ratio of 0.96, and Adventist Healthcare Shady Grove Medical Center (Rockville, MD) had an odds ratio of 0.86.