Abstract: ObjectiveTo investigate the effect of estimated glomerular filtration rate(eGFR) level on 1-year mortality in patients aged ≥75 years with acute ischemic stroke(AIS). 
MethodsClinical data of patients with acute stroke were included. Patients aged ≥75 years with AIS were selected and followed up for 3 months and 1 year respectively, and death events were recorded. The eGFR was treated as continuous variable and quartile grouped variable(group Q1-Q4). Multivariate Cox regression analysis was performed on the effect of eGFR level on 1-year mortality in patients aged ≥75 years with AIS. 
ResultsA total 506 patients aged ≥75 years with AIS were enrolled. The 3-month and 1-year mortality of Q1 group was significantly higher than that of other groups during follow-up, with statistical significance(P＜0.001). After adjustment for the related confounders, multivariate Cox regression analysis showed that for every 5 mL·min-1·（1.73 m2）-1 increase in eGFR level, the risk of 1-year mortality in patients aged ≥75 years with AIS decreased by 12.3%(HR=0.877, 95%CI: 0.8123-0.935，P＜0.001). Compared with the Q4 group, the risk of 3-month and 1-year mortality in group Q1 was significantly increased by 1.890 and 1.267 times, respectively(3 months: HR=2.890, 95%CI:1.010-8.241，P=0.048; 1-year: HR=2.267, 95%CI:1.118-4.596，P=0.023). Kaplan-Meier survival analysis found a significant decrease in survival in the Q1 group compared to the other groups. 
ConclusionReduced eGFR level is a risk factor for 1-year mortality in patients aged ≥75 years with AIS, and eGFR≤60.2 mL·min-1·（1.73 m2）-1 significantly increases the risk of 1-year mortality in patients aged ≥75 years with AIS. 

Key words: stroke, estimated glomerular filtration rate, mortality