Lower serum potassium associated with increased mortality in dialysis patients: A nationwide prospective observational cohort study in Korea

Sunhwa Lee, Eunjeong Kang, Kyung Don Yoo, Yunhee Choi, Dong Ki Kim, Kwon Wook Joo, Seung Hee Yang, Yong Lim Kim, Shin-Wook Kang, Chul Woo Yang, Nam Ho Kim, Yon Su Kim, Hajeong Lee

Research output: Contribution to journalArticle

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Abstract

Background Abnormal serum potassium concentration has been suggested as a risk factor for mortality in patients undergoing dialysis patients. We investigated the impact of serum potassium levels on survival according to dialysis modality. Methods A nationwide, prospective, observational cohort study for end stage renal disease patients has been ongoing in Korea since August 2008. Our analysis included patients whose records contained data regarding serum potassium levels. The relationship between serum potassium and mortality was analyzed using competing risk regression. Results A total of 3,230 patients undergoing hemodialysis (HD, 64.3%) or peritoneal dialysis (PD, 35.7%) were included. The serum potassium level was significantly lower (P < 0.001) in PD (median, 4.5 mmol/L; interquartile range, 4.0-4.9 mmol/L) than in HD patients (median, 4.9 mmol/L; interquartile range, 4.5-5.4 mmol/L). During 4.4 ± 1.7 years of follow-up, 751 patients (23.3%) died, mainly from cardiovascular events (n = 179) and infection (n = 120). In overall, lower serum potassium level less than 4.5 mmol/L was an independent risk factor for mortality after adjusting for age, comorbidities, and nutritional status (sub-distribution hazard ratio, 1.30; 95% confidence interval 1.10-1.53; P = 0.002). HD patients showed a U-shaped survival pattern, suggesting that both lower and higher potassium levels were deleterious, although insignificant. However, in PD patients, only lower serum potassium level (<4.5 mmol/L) was an independent predictor of mortality (sub-distribution hazard ratio, 1.35; 95% confidence interval 1.00-1.80; P = 0.048). Conclusion Lower serum potassium levels (<4.5 mmol/L) occur more commonly in PD than in HD patients. It represents an independent predictor of survival in overall dialysis, especially in PD patients. Therefore, management of dialysis patients should focus especially on reducing the risk of hypokalemia, not only that of hyperkalemia.

Original languageEnglish
Article numbere0171842
JournalPloS one
Volume12
Issue number3
DOIs
Publication statusPublished - 2017 Mar 1

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Dialysis
Korea
dialysis
cohort studies
Observational Studies
Korean Peninsula
Potassium
Cohort Studies
potassium
Mortality
Serum
Hazards
Survival
confidence interval
risk factors
Confidence Intervals
hyperkalemia
hypokalemia
Hyperkalemia
hemodialysis

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

Cite this

Lee, Sunhwa ; Kang, Eunjeong ; Yoo, Kyung Don ; Choi, Yunhee ; Kim, Dong Ki ; Joo, Kwon Wook ; Yang, Seung Hee ; Kim, Yong Lim ; Kang, Shin-Wook ; Yang, Chul Woo ; Kim, Nam Ho ; Kim, Yon Su ; Lee, Hajeong. / Lower serum potassium associated with increased mortality in dialysis patients : A nationwide prospective observational cohort study in Korea. In: PloS one. 2017 ; Vol. 12, No. 3.
@article{d4573630836a4c439b3a4e47ccbb8e96,
title = "Lower serum potassium associated with increased mortality in dialysis patients: A nationwide prospective observational cohort study in Korea",
abstract = "Background Abnormal serum potassium concentration has been suggested as a risk factor for mortality in patients undergoing dialysis patients. We investigated the impact of serum potassium levels on survival according to dialysis modality. Methods A nationwide, prospective, observational cohort study for end stage renal disease patients has been ongoing in Korea since August 2008. Our analysis included patients whose records contained data regarding serum potassium levels. The relationship between serum potassium and mortality was analyzed using competing risk regression. Results A total of 3,230 patients undergoing hemodialysis (HD, 64.3{\%}) or peritoneal dialysis (PD, 35.7{\%}) were included. The serum potassium level was significantly lower (P < 0.001) in PD (median, 4.5 mmol/L; interquartile range, 4.0-4.9 mmol/L) than in HD patients (median, 4.9 mmol/L; interquartile range, 4.5-5.4 mmol/L). During 4.4 ± 1.7 years of follow-up, 751 patients (23.3{\%}) died, mainly from cardiovascular events (n = 179) and infection (n = 120). In overall, lower serum potassium level less than 4.5 mmol/L was an independent risk factor for mortality after adjusting for age, comorbidities, and nutritional status (sub-distribution hazard ratio, 1.30; 95{\%} confidence interval 1.10-1.53; P = 0.002). HD patients showed a U-shaped survival pattern, suggesting that both lower and higher potassium levels were deleterious, although insignificant. However, in PD patients, only lower serum potassium level (<4.5 mmol/L) was an independent predictor of mortality (sub-distribution hazard ratio, 1.35; 95{\%} confidence interval 1.00-1.80; P = 0.048). Conclusion Lower serum potassium levels (<4.5 mmol/L) occur more commonly in PD than in HD patients. It represents an independent predictor of survival in overall dialysis, especially in PD patients. Therefore, management of dialysis patients should focus especially on reducing the risk of hypokalemia, not only that of hyperkalemia.",
author = "Sunhwa Lee and Eunjeong Kang and Yoo, {Kyung Don} and Yunhee Choi and Kim, {Dong Ki} and Joo, {Kwon Wook} and Yang, {Seung Hee} and Kim, {Yong Lim} and Shin-Wook Kang and Yang, {Chul Woo} and Kim, {Nam Ho} and Kim, {Yon Su} and Hajeong Lee",
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Lee, S, Kang, E, Yoo, KD, Choi, Y, Kim, DK, Joo, KW, Yang, SH, Kim, YL, Kang, S-W, Yang, CW, Kim, NH, Kim, YS & Lee, H 2017, 'Lower serum potassium associated with increased mortality in dialysis patients: A nationwide prospective observational cohort study in Korea', PloS one, vol. 12, no. 3, e0171842. https://doi.org/10.1371/journal.pone.0171842

Lower serum potassium associated with increased mortality in dialysis patients : A nationwide prospective observational cohort study in Korea. / Lee, Sunhwa; Kang, Eunjeong; Yoo, Kyung Don; Choi, Yunhee; Kim, Dong Ki; Joo, Kwon Wook; Yang, Seung Hee; Kim, Yong Lim; Kang, Shin-Wook; Yang, Chul Woo; Kim, Nam Ho; Kim, Yon Su; Lee, Hajeong.

In: PloS one, Vol. 12, No. 3, e0171842, 01.03.2017.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Lower serum potassium associated with increased mortality in dialysis patients

T2 - A nationwide prospective observational cohort study in Korea

AU - Lee, Sunhwa

AU - Kang, Eunjeong

AU - Yoo, Kyung Don

AU - Choi, Yunhee

AU - Kim, Dong Ki

AU - Joo, Kwon Wook

AU - Yang, Seung Hee

AU - Kim, Yong Lim

AU - Kang, Shin-Wook

AU - Yang, Chul Woo

AU - Kim, Nam Ho

AU - Kim, Yon Su

AU - Lee, Hajeong

PY - 2017/3/1

Y1 - 2017/3/1

N2 - Background Abnormal serum potassium concentration has been suggested as a risk factor for mortality in patients undergoing dialysis patients. We investigated the impact of serum potassium levels on survival according to dialysis modality. Methods A nationwide, prospective, observational cohort study for end stage renal disease patients has been ongoing in Korea since August 2008. Our analysis included patients whose records contained data regarding serum potassium levels. The relationship between serum potassium and mortality was analyzed using competing risk regression. Results A total of 3,230 patients undergoing hemodialysis (HD, 64.3%) or peritoneal dialysis (PD, 35.7%) were included. The serum potassium level was significantly lower (P < 0.001) in PD (median, 4.5 mmol/L; interquartile range, 4.0-4.9 mmol/L) than in HD patients (median, 4.9 mmol/L; interquartile range, 4.5-5.4 mmol/L). During 4.4 ± 1.7 years of follow-up, 751 patients (23.3%) died, mainly from cardiovascular events (n = 179) and infection (n = 120). In overall, lower serum potassium level less than 4.5 mmol/L was an independent risk factor for mortality after adjusting for age, comorbidities, and nutritional status (sub-distribution hazard ratio, 1.30; 95% confidence interval 1.10-1.53; P = 0.002). HD patients showed a U-shaped survival pattern, suggesting that both lower and higher potassium levels were deleterious, although insignificant. However, in PD patients, only lower serum potassium level (<4.5 mmol/L) was an independent predictor of mortality (sub-distribution hazard ratio, 1.35; 95% confidence interval 1.00-1.80; P = 0.048). Conclusion Lower serum potassium levels (<4.5 mmol/L) occur more commonly in PD than in HD patients. It represents an independent predictor of survival in overall dialysis, especially in PD patients. Therefore, management of dialysis patients should focus especially on reducing the risk of hypokalemia, not only that of hyperkalemia.

AB - Background Abnormal serum potassium concentration has been suggested as a risk factor for mortality in patients undergoing dialysis patients. We investigated the impact of serum potassium levels on survival according to dialysis modality. Methods A nationwide, prospective, observational cohort study for end stage renal disease patients has been ongoing in Korea since August 2008. Our analysis included patients whose records contained data regarding serum potassium levels. The relationship between serum potassium and mortality was analyzed using competing risk regression. Results A total of 3,230 patients undergoing hemodialysis (HD, 64.3%) or peritoneal dialysis (PD, 35.7%) were included. The serum potassium level was significantly lower (P < 0.001) in PD (median, 4.5 mmol/L; interquartile range, 4.0-4.9 mmol/L) than in HD patients (median, 4.9 mmol/L; interquartile range, 4.5-5.4 mmol/L). During 4.4 ± 1.7 years of follow-up, 751 patients (23.3%) died, mainly from cardiovascular events (n = 179) and infection (n = 120). In overall, lower serum potassium level less than 4.5 mmol/L was an independent risk factor for mortality after adjusting for age, comorbidities, and nutritional status (sub-distribution hazard ratio, 1.30; 95% confidence interval 1.10-1.53; P = 0.002). HD patients showed a U-shaped survival pattern, suggesting that both lower and higher potassium levels were deleterious, although insignificant. However, in PD patients, only lower serum potassium level (<4.5 mmol/L) was an independent predictor of mortality (sub-distribution hazard ratio, 1.35; 95% confidence interval 1.00-1.80; P = 0.048). Conclusion Lower serum potassium levels (<4.5 mmol/L) occur more commonly in PD than in HD patients. It represents an independent predictor of survival in overall dialysis, especially in PD patients. Therefore, management of dialysis patients should focus especially on reducing the risk of hypokalemia, not only that of hyperkalemia.

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