Low Serum Potassium Levels and Clinical Outcomes in Peritoneal Dialysis-International Results from PDOPPS

Simon J Davies; Junhui Zhao; Hal Morgenstern; Jarcy Zee; Brian Bieber; Douglas S Fuller; James A Sloand; Andreas Vychytil; Hideki Kawanishi; David W Johnson; Angela Yee-Moon Wang; Talerngsak Kanjananbuch; Sarinya Boongird; Thyago P Moraes; Sunil V Badve; Ronald L Pisoni; Jeffrey Perl; PDOPPS Dialysis Prescription and Fluid Management Working Group

doi:10.1016/j.ekir.2020.11.021

Low Serum Potassium Levels and Clinical Outcomes in Peritoneal Dialysis-International Results from PDOPPS

Kidney Int Rep. 2020 Nov 22;6(2):313-324. doi: 10.1016/j.ekir.2020.11.021. eCollection 2021 Feb.

Authors

Simon J Davies¹, Junhui Zhao², Hal Morgenstern^{3

4

5}, Jarcy Zee², Brian Bieber², Douglas S Fuller², James A Sloand⁶, Andreas Vychytil⁷, Hideki Kawanishi⁸, David W Johnson^{9

10

11}, Angela Yee-Moon Wang¹², Talerngsak Kanjananbuch¹³, Sarinya Boongird¹⁴, Thyago P Moraes¹⁵, Sunil V Badve^{16

17}, Ronald L Pisoni², Jeffrey Perl¹⁸; PDOPPS Dialysis Prescription and Fluid Management Working Group

Affiliations

¹ Faculty of Medicine and Health Sciences, Keele University, Keele, UK.
² Arbor Research Collaborative for Health, Ann Arbor, Michigan, USA.
³ Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan, USA.
⁴ Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, Michigan, USA.
⁵ Department of Urology, Medical School, University of Michigan, Ann Arbor, Michigan, USA.
⁶ JAS Renaissance, Chicago, Illinois, USA.
⁷ Medical University of Vienna, Vienna, Austria.
⁸ Tsuchiya General Hospital, Hiroshima, Japan.
⁹ Department of Nephrology, Princess Alexandra Hospital, Brisbane, Queensland, Australia.
¹⁰ Australasian Kidney Trials Network, University of Queensland, Brisbane, Queensland, Australia.
¹¹ Translational Research Institute, Brisbane, Queensland, Australia.
¹² University of Hong Kong, Queen Mary Hospital, Hong Kong, China.
¹³ Center of Excellence in Kidney Metabolic Disorders and Division of Nephrology, Department of Internal Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok Thailand.
¹⁴ Renal Unit, Department of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
¹⁵ Pontificia Universidade Catolica do Parana, Curitiba, Brazil.
¹⁶ St. George Hospital, Sydney, New South Wales, Australia.
¹⁷ The George Institute for Global Health, University of New South Wales Medicine, Sydney, New South Wales, Australia.
¹⁸ St. Michael's Hospital, Toronto, Ontario, Canada.

Abstract

Introduction: Hypokalemia, including normal range values <4 mEq/l, has been associated with increased peritonitis and mortality in patients with peritoneal dialysis. This study sought to describe international variation in hypokalemia, potential modifiable hypokalemia risk factors, and the covariate-adjusted relationship of hypokalemia with peritonitis and mortality.

Methods: Baseline serum potassium was determined in 7421 patients from 7 countries in the Peritoneal Dialysis Outcomes and Practice Patterns Study (2014-2017). Association of baseline patient and treatment factors with subsequent serum potassium <4 mEq/l was evaluated by logistic regression, whereas baseline serum potassium levels (4-month average and fraction of 4 months having hypokalemia) on clinical outcomes was assessed by Cox regression.

Results: Hypokalemia was more prevalent in Thailand and among black patients in the United States. Characteristics/treatments associated with potassium <4 mEq/l included protein-energy wasting indicators, lower urine volume, lower blood pressure, higher dialysis dose, greater diuretic use, and not being prescribed a renin-angiotensin system inhibitor. Persistent hypokalemia (all 4 months vs. 0 months over the 4-month exposure period) was associated with 80% higher subsequent peritonitis rates (at K <3.5 mEq/l) and 40% higher mortality (at K <4.0 mEq/l) after extensive case mix/potential confounding adjustments. Furthermore, adjusted peritonitis rates were higher if having mean serum K over 4 months <3.5 mEq/l versus 4.0-4.4 mEq/l (hazard ratio, 1.15 [95% confidence interval, 0.96-1.37]), largely because of Gram-positive/culture-negative infections.

Conclusions: Persistent hypokalemia is associated with higher mortality and peritonitis even after extensive adjustment for patient factors. Further studies are needed to elucidate mechanisms of these poorer outcomes and modifiable risk factors for persistent hypokalemia.

Keywords: PDOPPS; hypokalemia; mortality; peritoneal dialysis; peritonitis; potassium.

Grants and funding

R01 HS025756/HS/AHRQ HHS/United States