Abstract: Objective：To investigate the level of red blood cell volume distribution width in aged hemodialysis patients and analyze the clinical significance. Methods：Totally, 128 hemodialysis patients (48 males and 80 females) with mean age of (69.2±4.5) years old and mean dialysis vintage of (64.3±42.5) months from July 2017 to December 2017 were prospectively enrolled. Medical history was collected and parameters such as hemoglobin, red blood cell distribution width (RDW), serum electrolytes, high sensitivity Creactive protein (hsCRP), serum albumin, ferritin, and intact parathyroid hormone (iPTH) were measured before the midweek hemodialysis. Pearson correlation analysis and multiple linear stepwise regression model were applied to analyze the relationship between these clinical parameters and RDW. Curve fitting model was used to analyze the clinical parameters that may be nonlinearly correlated with RDW. All patients were followed up for 12 months. The primary end point was death and the secondary end point was cardiovascular events. Survival analysis was performed with KaplanMeier survival curves between the higher RDW group and the lower RDW group. Cox proportional hazards model was used to explore independent predictors related to prognosis. Results：The mean RDW was （［16.24±2.22］%, ［14.0 to 20.4］% ［median 15.1%］） in all patients, of which 105 (82.1%) were abnormal. Pearson correlation analysis showed that RDW was positively correlated with dialysis vintage, EPO dose, hsCRP, and interdialytic weight gain ratio. RDW was negatively correlated with serum albumin. Multivariate linear regression model showed that RDW was significantly associated with serum albumin and EPO dose (P＜0.01). In curve fitting estimation, the quadratic equation had the goodness of fitting with statistical significance (P＜0.001). A total of 6 patients died during the 12month followup with 4 patients in the higher RDW group and 2 patients in the lower RDW group. There was no significant difference between the two groups. During the followup, 36 cases of various cardiovascular and cerebrovascular events occurred in which 26 cases in the higher RDW group and 10 cases in the lower RDW group. KaplanMeier analysis indicated that there was a statistically significant difference in the incidence of cardiovascular events between the higher RDW group and the lower RDW group (logrank =16.224, P＜0.001). Univariate Cox regression showed that RDW level was positively correlated with cardiovascular and cerebrovascular events, while hemoglobin, serum albumin level were negatively correlated with cardiovascular and cerebrovascular events. Multivariate Cox regression model showed that RDW (HR=1.231, P=0.015) and serum albumin level (HR=0.964, P＜0.001) were independent predictors of cardiovascular and cerebrovascular events in elderly hemodialysis patients within 12 months. Conclusions：Increased RDW was common in elderly hemodialysis patients, which might be related to anemia, dialysis age, nutritional status, inflammatory status, cardiac function, EPO dose and response. The increased RDW level was associated with clinical cardiovascular and cerebrovascular events in elderly hemodialysis patients.