The effects of pre-existing hyponatremia and subsequent-developing acute kidney injury on in-hospital mortality: A retrospective cohort study

Sung Woo Lee, Seon Ha Baek, Shin Young Ahn, Ki Young Na, Dong Wan Chae, Ho Jun Chin, Sejoong Kim

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


Background and Objectives Both hyponatremia and acute kidney injury (AKI) are common and harmful in hospitalized patients. However, their combined effects on patient mortality have been little studied. Methods We retrospectively enrolled 19191 adult patients who were admitted for 1 year. Pre-existing hyponatremia was defined as a serum sodium level < 135 mmol/L on the first measurement of their admission. AKI was defined as a rise in serum creatinine by ô 26.5 μmol/L or ô 1.5 times of the baseline value of creatinine during the hospital stay. Results The prevalence of pre-existing hyponatremia was 8.2%. During a median 6.0 days of hospital stay, the incidence rates of AKI and in-hospital patient mortality were 5.1% and 0.9%, respectively. Pre-existing hyponatremia independently predicted AKI development and inhospital mortality(adjusted hazard ratio [HR] 1.300, P = 0.004; HR 2.481, P = 0.002, respectively). Pre-existing hyponatremia and subsequent development of AKI increased in-hospital mortality by 85 times, compared to the patients with normonatremia and no AKI. In subgroup analysis, the AKI group showed higher rates of de novo hypernatremia than the non-AKI group during the admission. De novo hypernatremia, which might be associated with over-correction of hyponatremia, increased in-hospital mortality(HR 3.297, P <0.001), and patients with AKI showed significantly higher rates of de novo hypernatremia than patients without AKI (16.2% vs. 1.4%, P < 0.001, respectively).Conclusion Pre-existing hyponatremia may be associated with the development of AKI in hospitalized patients, and both hyponatremia and hospital-acquired AKI could have a detrimental effect on short term patient mortality, which might be related to the inappropriate correction of hyponatremia in AKI patients.

Original languageEnglish
Article numbere0162990
JournalPloS one
Issue number9
Publication statusPublished - 2016 Sept
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2016 Lee et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

ASJC Scopus subject areas

  • General


Dive into the research topics of 'The effects of pre-existing hyponatremia and subsequent-developing acute kidney injury on in-hospital mortality: A retrospective cohort study'. Together they form a unique fingerprint.

Cite this