Abstract: Ｏｂｊｅｃｔｉｖｅ：To investigate the effect of serum potassium concentrations on all-cause mortality and cardiovascular disease (CVD) mortality within 3 months in maintenance hemodialysis (MHD) patients.
Ｍｅｔｈｏｄｏｌｏｇｙ：A multicenter retrospective cohort study. The general information and laboratory indicators of patients newly entered MHD in the registration system of Zhejiang province dialysis quality control center from January 1, 2010 to December 31, 2019 were collected. Serum potassium was selected as the highest value of serum potassium before dialysis within 3 months before the end of follow-up. The patients were divided into 8 groups according to the serum potassium level, and the Kaplan-Meier method was used to compare the survival differences between all-cause mortality and CVD mortality in each group, and the multivariate COX regression model was used to analyze the relationship between serum potassium level and all-cause mortality and CVD mortality.
Ｒｅｓｕｌｔｓ：A total of 21 861 patients aged (61.1±15.4) years old were included, including 13 465 males (61.6％), and 10 132 patients (46.3％) with cardiovascular diseases. The median follow-up time was 34(19, 56) months, 4 635 cases (21.2％) all-cause died, including 1 319 cases (6.0％) with cardiovascular disease. 759 patients (3.5％) with serum potassium<3.5 mmol/L, 9 782 patients (44.7％) with serum potassium≥5.0 mmol/L, and 5 420 patients (24.7％) with serum potassium≥5.5 mmol/L. Kaplan-Meier survival curve showed that the risk of all-cause mortality (Log-rank test, χ2=248.0, P<0.001), and the risk of cardiovascular mortality (Log-rank test, χ2=96.6, P<0.001) were significantly different among eight groups. Multivariate COX regression analysis showed that serum potassium level≥5.5 mmol/L was an independent risk factor for all-cause mortality(5.5≤K<6.0 mmol/L, HR=1.34,95％CI 1.08～1.67,P=0.008;6.0≤K<6.5 mmol/L,HR=1.53,95％CI 1.18～2.00,P=0.001;K≥6.5 mmol/L,HR=2.33 95％CI 1.80～3.01,P<0.001) and CVD mortality(5.5≤K<6.0 mmol/L,HR=1.65,95％CI 1.13～2.43,P=0.001;6.0≤K<6.5 mmol/L,HR=1.75,95％CI 1.08～2.82,P=0.023;K≥6.5 mmol/L,HR=2.70,95％CI 1.70～4.29,P<0.001) within 3 months in MHD patients.
Ｃｏｎｃｌｕｓｉｏｎ：Serum potassium≥5.5 mmol/L was an independent risk factor for all-cause mortality and CVD mortality within 3 months in MHD patients, and the higher the serum potassium level, the greater the risk of death.

Key words: hemodialysis, serum potassium, mortality, cardiovascular disease