Objective To explore the correlation between the variability of blood potassium level and risk of renal insufficiency(RI)in elderly heart failure(HF)patients with chronic systolic dys-function.Methods A total of 157 consecutive elderly patients with chronic HF admitted in De-partment of Cardiovascular Medicine of Wuhu First People's Hospital from January 2020 to No-vember 2022 were included,and according to whether RI occurred or not,they were divided into the RI group(36 cases)and the non-RI group(121 cases).Their general data and blood potassium variability was collected and recorded,and all of them were followed up for 6 months.Multivariate logistic regression analysis was applied for the correlation between blood potassium variability and RI in the elderly patients with chronic HF.Results The range of change,maximum fluctuation rate and coefficient of variation for blood potassium were significantly higher in the RI group than the non-RI group(P＜0.01).Multivariate logistic regression analysis showed that length of hospi-tal stay(OR=1.174,95％CI:1.067-1.292,P=0.001),age(OR=1.939,95％CI:1.309-2.872,P=0.001),albumin level(OR=0.866,95％CI:0.751-0.997,P=0.046),and range of change(OR=1.774,95％CI:1.519-2.071,P=0.016),maximum fluctuation rate(OR=1.631,95％CI:1.265-2.167,P=0.001)and coefficient of variation of blood potassium(OR=1.670,95％CI:1.212-2.230,P=0.002)were independent influencing factor for RI in the patients.Logistic re-gression analysis indicated that the range of serum potassium change≥0.80,the maximum fluctu-ation rate ≥0.40,and the coefficient of variation of serum potassium ≥8.20 were closely correla-ted with RI in elderly patients with chronic HF(P＜0.01).Conclusion High variability of blood potassium level is a risk factor for RI in elderly patients with chronic HF.