Prognostic value of red cell distribution width in maintenance hemodialysis patients

Abstract

Objective To investigate the relationship of red cell distribution width (RDW) with all-cause mortality and cardiovascular disease (CVD) mortality in patients undergoing maintenance hemodialysis (MHD). Methods A retrospective analysis was performed in patients who initiated MHD from January 2008 to September 2017 in the hemodialysis center of the Second Affiliated Hospital of Soochow University. Basic data on demographic, dialysis and laboratory were collected, and echocardiography indicators and clinical outcomes were recorded. Patients were divided into four groups according to the quartile of RDW level. Kaplan-Meier survival analysis was used to compare the difference of survival rate among the groups. Cox regression analysis was used to analyze the risk factors of all-cause and CVD-related mortality, and predictive value of RDW for all-cause and CVD-related death in hemodialysis patients. Results A total of 268 MHD patients were enrolled in this study with age of (60.9±15.8) years and dialysis duration of (58.1±9.1) months, including 159 males (59.3%). Kaplan-Meier survival analysis showed that the 1-year overall survival rates of Q1 group (RDW≤13.8%, n=61), Q2 group (RDW 13.9%-14.6%, n=66), Q3 group (RDW 14.7%-15.6%, n=73) and Q4 group (RDW≥15.7%, n=68) were 96.8%, 95.1%, 93.1% and 85.7% respectively; 3-year overall survival rates were 88.5%, 87.5%, 59.2% and 51.8% respectively; 5-year overall survival rates were 71.5%, 65.4%, 33.6% and 17.7% respectively; The difference between the groups was statistically significant (all P<0.01). The 1-year CVD survival rates were 98.4%, 96.6%, 95.8% and 92.4% respectively; 3-year CVD survival rates were 94.8%, 92.5%, 84.4% and 70.4% respectively; 5-year CVD survival rates were 86.9%, 81.3%, 65.6% and 51.3% respectively; The difference between the groups was statistically significant (all P<0.01). Multivariate Cox regression analysis showed that RDW≥15.7% was an independent risk factor for all-cause and CVD-related mortality in MHD patients. The risk of all-cause mortality in Q4 group was 3.098 times higher than that in Q1 group (95% CI 1.072-8.950, P=0.037) and the risk of CVD-related mortality was 2.661 times (95% CI 1.111-8.342, P=0.048). Receiver operating characteristic curve (ROC) showed that RDW=14.85% was the best cut-off point for predicting the all-cause mortality in HD patients (P<0.01), RDW=15.45% was the best cut-off point for predicting the cardiovascular disease mortality (P<0.01), and RDW=14.45% had a higher 5-year survival rate (P<0.01). Conclusion RDW can independently predict all-cause and CVD-related mortality risk in hemodialysis patients, and it has important value for prognosis. Key words: Erythrocytes; Renal dialysis; Prognosis; Cardiovascular diseases