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

Journal website https://www.jocmr.org

Review

Volume 15, Number 2, February 2023, pages 59-67

Stratification of Acute Kidney Injury Risk, Disease Severity, and Outcomes by Electrolyte Disturbances

**Table 1.** Summary of All Studies Discussed in the Main Text
Reference/year	Design	Outcome	Summary
The outcome variables of interest are AKI onset during in-hospital treatment, in-hospital death, the need for dialysis due to AKI and recovery of kidney function until demission. Fields remain empty if no particular information have been provided. AKI: acute kidney injury; ICU: intensive care unit; COVID-19: coronavirus disease 2019; ED: emergency department; NA: not available.
Serum sodium
Peres et al, 2015 [17]	Retrospective, single ICU, 152 AKI patients	No association with dysnatremia	Hypernatremia independently predictive	No association with dysnatremia	-	Admission dysnatremia has limited value with regard to AKI-related outcome variables at the ICU
Lee et al, 2016 [18]	Retrospective, 1-year period, > 19,000 hospitalized patients	Hyponatremia independently predictive	Hyponatremia independently predictive	-	-	Hospital admission hyponatremia suitable for AKI prediction
Gao et al, 2019 [19]	Retrospective, > 13,000 ICU-treated AKI patients	-	Hyper- and hyponatremia predictive	Dysnatremia not predictive	-	ICU admission dysnatremia has limited value in dialysis risk prediction of AKI subjects
Bae at al, 2020 [20]	Retrospective, 2-year period, 412 subjects with insomnia	Hyponatremia not predictive	Hyponatremia associated with all-cause mortality	-	-	Hyponatremia not AKI predictive over 24 months
Woitok et al, 2020 [24]	Retrospective, cross-sectional, 2-year period, > 1,700 subjects, ED	-	Hyper- and hyponatremia predictive in AKI subjects	-	-	ED admission dysnatremia mortality predictive in established AKI
Zhi et al, 2021 [25]	Retrospective, 6-year period, 590 ICU-treated patients	Hyponatremia predictive	Hypernatremia death predictive in AKI	-	-	Admission hyponatremia potentially useful in AKI risk prediction under ICU conditions
Basalely et al, 2021 [26]	Secondary analysis of 1,979 neonates included in the AWAKEN trial [28]	Dysnatremia not predictive	Hyper- and hyponatremia predicted mortality	-	-	Dysnatremia not suitable for no AKI prediction in neonates
Tzoulis et al, 2021 [28]	Retrospective, longitudinal cohort study, 488 patients, 8-week period, COVID-19 patients	Dysnatremia not predictive	Hypernatremia predictive for in-hospital death	-	-	Admission dysnatremia not suitable for AKI prediction
Serum potassium
Gao et al, 2019 [19] - see above	Retrospective, > 13,000 ICU-treated AKI patients	-	Higher 90-day mortality in hyponatremic AKI individuals with simultaneous hyperkalemia	Admission serum potassium not predictive	-	Additional potassium analysis in hyponatremic AKI individuals helpful in mortality prediction
Ravioli et al, 2021 [31]	Retrospective, cross-sectional, 2-year period, > 1,700 patients, ED, AKI subjects	-	Dyskalemia predictive in established AKI	-	-	NA
Lombardi et al, 2022 [32]	Retrospective, cohort study, 5-year period, no AKI from day 1 to 10 of the hospital stay, 21,830 hospital admissions	Hyperkalemia and potassium variability associated with AKI onset	-	-	-	Increased serum potassium useful in AKI prediction several days in advance
Serum calcium
Thongprayoon et al, 2018 [34]	Retrospective, 5-year period, 25,844 hospitalized patients, six groups defined, depending on the total serum calcium level	4 out of 6 distinct calcium ranges AKI predictive	-	-	-	Total calcium useful with regard to the prediction of AKI onset
Thongprayoon et al, 2020 [35]	Retrospective, 5-year period, 12,784 patients, six groups defined, depending on the serum level of ionized calcium	U-shaped association between ionized calcium and AKI onset	-	-	-	Ionized calcium useful with regard to the prediction of AKI onset
Serum phosphate
Moon et al, 2019 [36]	Retrospective, 1-year period, 20,686 patients, four groups defined, depending on the serum phosphate level	Higher AKI odds ratios in quartiles 3 and 4 as compared to quartile 1	-	-	-	Certain serum phosphate ranges are associated with higher AKI risk
Saour et al, 2020 [37]	Prospective, observational, single center, 260 individuals, post-cardiac surgery AKI	-	-	-	Phosphate decreases of 25% or more after 24 h predictive	Limited value with regard to AKI-related outcome variables
Thongprayoon et al, 2018 [33]	Retrospective, 5-year period, 5,036 patients, six groups defined, depending on the total serum phosphate level	Serum phosphate > 4.4 mg/dL associated with increased AKI risk	-	-	-	Severe hyperphosphatemia predicts AKI onset
Chen et al, 2021 [38]	Retrospective investigation in 823 COVID-19 patients	Hypophosphatemia predictive	-	-	-	Hyperphosphatemia independently AKI predictive
Lemerle et al, 2022 [39]	Retrospective, 11-year period, 120 patients, tumor lysis syndrome	Hyperphosphatemia predictive	-	-	-	Hyperphosphatemia AKI predictive

Table 1. Summary of All Studies Discussed in the Main Text

Reference/year

Design

Outcome

Summary

AKI onset

Death

Dialysis

Recovery of kidney function

The outcome variables of interest are AKI onset during in-hospital treatment, in-hospital death, the need for dialysis due to AKI and recovery of kidney function until demission. Fields remain empty if no particular information have been provided. AKI: acute kidney injury; ICU: intensive care unit; COVID-19: coronavirus disease 2019; ED: emergency department; NA: not available.

Serum sodium

Peres et al, 2015 [17]

Retrospective, single ICU, 152 AKI patients

No association with dysnatremia

Hypernatremia independently predictive

No association with dysnatremia

Admission dysnatremia has limited value with regard to AKI-related outcome variables at the ICU

Lee et al, 2016 [18]

Retrospective, 1-year period, > 19,000 hospitalized patients

Hyponatremia independently predictive

Hospital admission hyponatremia suitable for AKI prediction

Gao et al, 2019 [19]

Retrospective, > 13,000 ICU-treated AKI patients

Hyper- and hyponatremia predictive

Dysnatremia not predictive

ICU admission dysnatremia has limited value in dialysis risk prediction of AKI subjects

Bae at al, 2020 [20]

Retrospective, 2-year period, 412 subjects with insomnia

Hyponatremia not predictive

Hyponatremia associated with all-cause mortality

Hyponatremia not AKI predictive over 24 months

Woitok et al, 2020 [24]

Retrospective, cross-sectional, 2-year period, > 1,700 subjects, ED

Hyper- and hyponatremia predictive in AKI subjects

ED admission dysnatremia mortality predictive in established AKI

Zhi et al, 2021 [25]

Retrospective, 6-year period, 590 ICU-treated patients

Hyponatremia predictive

Hypernatremia death predictive in AKI

Admission hyponatremia potentially useful in AKI risk prediction under ICU conditions

Basalely et al, 2021 [26]

Secondary analysis of 1,979 neonates included in the AWAKEN trial [28]

Dysnatremia not predictive

Hyper- and hyponatremia predicted mortality

Dysnatremia not suitable for no AKI prediction in neonates

Tzoulis et al, 2021 [28]

Retrospective, longitudinal cohort study, 488 patients, 8-week period, COVID-19 patients

Dysnatremia not predictive

Hypernatremia predictive for in-hospital death

Admission dysnatremia not suitable for AKI prediction

Serum potassium

Gao et al, 2019 [19] - see above

Retrospective, > 13,000 ICU-treated AKI patients

Higher 90-day mortality in hyponatremic AKI individuals with simultaneous hyperkalemia

Admission serum potassium not predictive

Additional potassium analysis in hyponatremic AKI individuals helpful in mortality prediction

Ravioli et al, 2021 [31]

Retrospective, cross-sectional, 2-year period, > 1,700 patients, ED, AKI subjects

Dyskalemia predictive in established AKI

Lombardi et al, 2022 [32]

Retrospective, cohort study, 5-year period, no AKI from day 1 to 10 of the hospital stay, 21,830 hospital admissions

Hyperkalemia and potassium variability associated with AKI onset

Increased serum potassium useful in AKI prediction several days in advance

Serum calcium

Thongprayoon et al, 2018 [34]

Retrospective, 5-year period, 25,844 hospitalized patients, six groups defined, depending on the total serum calcium level

4 out of 6 distinct calcium ranges AKI predictive

Total calcium useful with regard to the prediction of AKI onset

Thongprayoon et al, 2020 [35]

Retrospective, 5-year period, 12,784 patients, six groups defined, depending on the serum level of ionized calcium

U-shaped association between ionized calcium and AKI onset

Ionized calcium useful with regard to the prediction of AKI onset

Serum phosphate

Moon et al, 2019 [36]

Retrospective, 1-year period, 20,686 patients, four groups defined, depending on the serum phosphate level

Higher AKI odds ratios in quartiles 3 and 4 as compared to quartile 1

Certain serum phosphate ranges are associated with higher AKI risk

Saour et al, 2020 [37]

Prospective, observational, single center, 260 individuals, post-cardiac surgery AKI

Phosphate decreases of 25% or more after 24 h predictive

Limited value with regard to AKI-related outcome variables

Thongprayoon et al, 2018 [33]

Retrospective, 5-year period, 5,036 patients, six groups defined, depending on the total serum phosphate level

Serum phosphate > 4.4 mg/dL associated with increased AKI risk

Severe hyperphosphatemia predicts AKI onset

Chen et al, 2021 [38]

Retrospective investigation in 823 COVID-19 patients

Hypophosphatemia predictive

Hyperphosphatemia independently AKI predictive

Lemerle et al, 2022 [39]

Retrospective, 11-year period, 120 patients, tumor lysis syndrome

Hyperphosphatemia predictive

Hyperphosphatemia AKI predictive