J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

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Review

Volume 15, Number 8-9, September 2023, pages 399-405

Hypernatremia: Epidemiology and Predictive Role in Emerging and Established Acute Kidney Injury

**Table 1.** Epidemiology and Outcomes of In-Hospital Diagnosed Hypernatremia
Reference	Design	Hypernatremia prevalence	Outcomes
The studies have been listed according to the publication date (older to more recent). ICU: intensive care unit.
Bataille et al, 2014 [17]	Observational, retrospective, 54,753 emergency department admissions	Severe hypernatremia (> 150 mmol/L) in 85 individuals	Mortality rate 25%, slow correction of serum sodium independently death predictive
Felizardo Lopes et al, 2015 [18]	Observational, retrospective, single-center, 1,945 hospitalizations considered	2.6%	In-hospital mortality of hypernatremic patients significantly higher as compared to all other individuals (43 vs. 2%)
Alansari et al, 2016 [19]	Observational, retrospective, single-center (one surgical ICU), exclusion of patients with therapeutic need of hypernatremia, n = 865	5.8%	Intensive care mortality 40%
Hu et al, 2016 [20]	Observational, retrospective, single-center (neurologic ICU), normonatremia on admission, exclusion of patients with impaired kidney function, n = 450	Mild hypernatremia in 142 individuals, severe hypernatremia in 86 patients	Peak serum sodium independently death predictive
Hu et al, 2017 [21]	Prospective investigation in more than 90,000 individuals	1.9%	Hypernatremia in general, in-hospital-acquired, and persistent hypernatremia predicted in-hospital death
Imaizumi et al, 2017 [22]	Retrospective study, intensive care-treated patients without dysnatremia on admission	6.8%	Hypernatremia predictive of 28-days mortality (hazard ratio 3.07)
Thongprayoon et al, 2020 [23]	Retrospective data from 2011 to 2023, long-term outcome data from 55,901 discharged patients, last measured serum sodium before discharge defined category	About 9.2%	Highest 1-year mortality risk in patients with serum sodium ≥ 148 mmol/L
Castello et al, 2021 [25]	Subanalysis of the need-speed trial [24], septic individuals, serum sodium analysis at the time of emergency department admission	5.7%	Hypernatremia associated with higher mortality than eu- and hyponatremia; hypernatremia predicted death at days 7 and 30
Del Rio et al, 2022 [26]	Retrospective, monocentric evaluation, 2,945 hospitalized cancer patients, comparisons to matched controls with hyponatremia	3.16%	Higher mortality (30.1 vs. 8.6%) and lower median survival times (1.5 vs. 11.7 months) in hyper- as compared to hyponatremic patients
Seo et al, 2020 [27]	Retrospective study in patients with terminal cancer, n = 487, serum sodium analysis on admission to hospice-palliative care	3%	Hypernatremia mortality predictive
Lee et al, 2023 [28]	Retrospective, monocentric evaluation, neurosurgical ICU, screening of 1,146 patients from a 6-years period, propensity score matching	30.8%	Moderate and severe hypernatremia associated with in-hospital and 28-days mortality; mild hypernatremia associated with the highest survival rates at all

Table 1. Epidemiology and Outcomes of In-Hospital Diagnosed Hypernatremia

Reference

Design

Hypernatremia prevalence

Outcomes

The studies have been listed according to the publication date (older to more recent). ICU: intensive care unit.

Bataille et al, 2014 [17]

Observational, retrospective, 54,753 emergency department admissions

Severe hypernatremia (> 150 mmol/L) in 85 individuals

Mortality rate 25%, slow correction of serum sodium independently death predictive

Felizardo Lopes et al, 2015 [18]

Observational, retrospective, single-center, 1,945 hospitalizations considered

2.6%

In-hospital mortality of hypernatremic patients significantly higher as compared to all other individuals (43 vs. 2%)

Alansari et al, 2016 [19]

Observational, retrospective, single-center (one surgical ICU), exclusion of patients with therapeutic need of hypernatremia, n = 865

5.8%

Intensive care mortality 40%

Hu et al, 2016 [20]

Observational, retrospective, single-center (neurologic ICU), normonatremia on admission, exclusion of patients with impaired kidney function, n = 450

Mild hypernatremia in 142 individuals, severe hypernatremia in 86 patients

Peak serum sodium independently death predictive

Hu et al, 2017 [21]

Prospective investigation in more than 90,000 individuals

1.9%

Hypernatremia in general, in-hospital-acquired, and persistent hypernatremia predicted in-hospital death

Imaizumi et al, 2017 [22]

Retrospective study, intensive care-treated patients without dysnatremia on admission

6.8%

Hypernatremia predictive of 28-days mortality (hazard ratio 3.07)

Thongprayoon et al, 2020 [23]

Retrospective data from 2011 to 2023, long-term outcome data from 55,901 discharged patients, last measured serum sodium before discharge defined category

About 9.2%

Highest 1-year mortality risk in patients with serum sodium ≥ 148 mmol/L

Castello et al, 2021 [25]

Subanalysis of the need-speed trial [24], septic individuals, serum sodium analysis at the time of emergency department admission

5.7%

Hypernatremia associated with higher mortality than eu- and hyponatremia; hypernatremia predicted death at days 7 and 30

Del Rio et al, 2022 [26]

Retrospective, monocentric evaluation, 2,945 hospitalized cancer patients, comparisons to matched controls with hyponatremia

3.16%

Higher mortality (30.1 vs. 8.6%) and lower median survival times (1.5 vs. 11.7 months) in hyper- as compared to hyponatremic patients

Seo et al, 2020 [27]

Retrospective study in patients with terminal cancer, n = 487, serum sodium analysis on admission to hospice-palliative care

Hypernatremia mortality predictive

Lee et al, 2023 [28]

Retrospective, monocentric evaluation, neurosurgical ICU, screening of 1,146 patients from a 6-years period, propensity score matching

30.8%

Moderate and severe hypernatremia associated with in-hospital and 28-days mortality; mild hypernatremia associated with the highest survival rates at all

**Table 2.** Hypernatremia in AKI Risk Prediction
Reference	Design	Endpoints	Findings
ICU: intensive care unit; AKI: acute kidney injury; KRT: kidney replacement therapy; KDIGO: Kidney Disease: Improving Global Outcomes.
Kumar et al, 2015 [34]	Retrospective study in patients with subarachnoid hemorrhage, n = 736	AKI incidence from 72 h until 14 days after admission, AKI diagnosis according to KDIGO [40]	Therapeutic sodium administration associated with AKI onset per se, every increase in serum sodium by 1 mmol/L associated with an AKI hazard ratio increase of 5.4%
Peres et al, 2015 [36]	Retrospective, single-center analysis, ICU, n = 152	AKI onset and ICU mortality	Hypernatremia predicted ICU death but not AKI
Mendes et al, 2015 [37]	Secondary analysis of 772 individuals from a 2011 published prospective trial [38]	In-hospital mortality	Highest mortality in subjects with hypernatremia and AKI, hypernatremia independently mortality-predictive
Woitok et al, 2020 [6]	Retrospective cross-sectional study in emergency department patients	Death in AKI patients	Hypo- and hypernatremia death predictive
Marahrens et al, 2023 [39]	Retrospective, observational, inclusion of patients with de novo AKI, serum sodium analysis at five pre-defined timepoints	Need of KRT, in-hospital death	Increase of the relative risk of in-hospital death by 8% with every unit of serum sodium increase

Table 2. Hypernatremia in AKI Risk Prediction

Reference

Design

Endpoints

Findings

ICU: intensive care unit; AKI: acute kidney injury; KRT: kidney replacement therapy; KDIGO: Kidney Disease: Improving Global Outcomes.

Kumar et al, 2015 [34]

Retrospective study in patients with subarachnoid hemorrhage, n = 736

AKI incidence from 72 h until 14 days after admission, AKI diagnosis according to KDIGO [40]

Therapeutic sodium administration associated with AKI onset per se, every increase in serum sodium by 1 mmol/L associated with an AKI hazard ratio increase of 5.4%

Peres et al, 2015 [36]

Retrospective, single-center analysis, ICU, n = 152

AKI onset and ICU mortality

Hypernatremia predicted ICU death but not AKI

Mendes et al, 2015 [37]

Secondary analysis of 772 individuals from a 2011 published prospective trial [38]

In-hospital mortality

Highest mortality in subjects with hypernatremia and AKI, hypernatremia independently mortality-predictive

Woitok et al, 2020 [6]

Retrospective cross-sectional study in emergency department patients

Death in AKI patients

Hypo- and hypernatremia death predictive

Marahrens et al, 2023 [39]

Retrospective, observational, inclusion of patients with de novo AKI, serum sodium analysis at five pre-defined timepoints

Need of KRT, in-hospital death

Increase of the relative risk of in-hospital death by 8% with every unit of serum sodium increase