Changes in whole blood viscosity during hemodialysis and mortality in patients with end-stage renal disease

Whole blood viscosity (WBV) plays a role in hemorheology and is determined by many factors such as red blood cell factors, plasma protein and blood volume. As WBV changes during hemodialysis, mortality may be due to changes in WBV in patients on hemodialysis. However, there are few prospective data on the relationship between changes in WBV and overall mortality in dialysis patients. We tried to investigate the correlations between values of WBV at variable shear rates before and after hemodialysis and overall or atherosclerosis-related mortality in patients with end-stage kidney disease.Forty-three patients receiving hemodialysis were enrolled in this study. In this 5.8-year prospective observational study, analyses of the effects of WBV at shear rates of 300 s-1 (systolic WBV; SBV), 5 s-1 (diastolic WBV5; DBV5), and 1 s-1 (diastolic WBV1; DBV1) during dialysis on all-cause and atherosclerotic mortality was performed.Among a total of 43 patients, 27 (62.7%) died over the course of the study. Thirteen deaths were caused by atherosclerotic events. A high degree of change in WBV at shear rates of 300 s-1 and 5 s-1 during hemodialysis (ΔSBV, ΔDBV5) was positively correlated with overall mortality (HR = 4.688, 95% confidence interval [CI], 1.269-17.319, p = 0.020; HR = 3.941, 95% CI, 1.057-14.701, p = 0.041, respectively). A high degree of change in diastolic blood pressure (ΔDBP) during hemodialysis was also positively correlated with overall mortality (HR = 3.035, 95% CI, 1.039-8.867, p = 0.042). However, comparative analysis between WBV at shear rates of 300 s-1, 5 s-1, and 1 s-1 and overall mortality did not reveal any significant relationships. Kaplan-Meier analysis revealed that the all-cause mortality was significantly higher in patients from a high degree of change of WBV at shear rates of 300 s-1, compared to those from the moderate or low degree of changes of WBV at shear rates of 300 s-1 (p = 0.020, log-rank test). Survival rate in high ΔDBP was lower than that of moderate or low ΔDBP group in Kaplan-Meier survival analysis (p = 0.004, log-rank test).Our data showed that a high degree of change in WBV at variable shear rates during hemodialysis might impact overall survival in patients with end-stage kidney disease. However, large-scale studies to evaluate the relationship of WBV with overall mortality and atherosclerotic mortality will be needed.