Hospitalized patients with serum sodium levels outside of the optimal range when they are discharged are at increased risk of dying within 1 year, investigators reported at the American Society of Nephrology’s Kidney Week 2020 Reimagined virtual conference.

Between the dysnatremias, hypernatremia at hospital discharge more strongly influenced 1-year mortality than hyponatremia at discharge.

In a single-center study of 59,901 hospitalized patients, a team led by Charat Thongprayoon, MD, of Mayo Clinic in Rochester, Minnesota, found that 1-year mortality rates were 26.1%, 15.5%, 11.6%, 17.2%, and 49.4% for patients with serum sodium values of 132 or less, 133-137, 138-142, 143-147, and 148 mEq/L or higher, respectively.

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Compared with a reference value of 138-142 mEq/L, those with values of 132 or less, 133-137, 143-147, and 148 mEq/L or higher had significantly increased odds of 1-year mortality by a factor of 1.43, 1.10, 1.35, and 3.86 (all P values less than or equal to .001), respectively, after adjustment for age, sex, race, admission serum sodium values, Charlson comorbidity score, and other potential confounders, according to the investigators.

“The optimal range of serum sodium at hospital discharge was 138 to 142 mEq/L, but almost half of hospitalized patients were discharged with serum sodium outside of this optimal range,” Dr Thongprayoon told Renal & Urology News. “Targeting serum sodium to the optimal range before hospital discharge may potentially lead to more favorable long-term survival.”

The study population was 54% male and 93% White. Discharge serum sodium values were the last measurements within 48 hours before discharge.


Thongprayoon C, Cheungpasitporn W, Chewcharat A, et al. The prognostic importance of serum sodium levels at hospital discharge and 1-year mortality among hospitalized patients. Presented at: Kidney Week 2020 Reimagined virtual conference. Poster PO1437.