The impact of blood flow rate during hemodialysis on all-cause mortality

Background/Aims: Inadequacy of dialysis is associated with morbidity and mortality in chronic hemodialysis (HD) patients. Blood flow rate (BFR) during HD is one of the important determinants of increasing dialysis dose. However, the optimal BFR is unclear. In this study, we investigated the impact of the BFR on all-cause mortality in chronic HD patients. Methods: Prevalent HD patients were selected from Clinical Research Center registry for end-stage renal disease cohort in Korea. We categorized patients into two groups by BFR < 250 and ${\geq}250mL/min$ according to the median value of BFR 250 mL/min in this study. The primary outcome was all-cause mortality. Results: A total of 1,129 prevalent HD patients were included. The number of patients in the BFR < 250 mL/min was 271 (24%) and in the $BFR{\geq}250mL/min$ was 858 (76%). The median follow-up period was 30 months. Kaplan-Meier analysis showed that the mortality rate was significantly higher in patients with BFR < 250 mL/min than those with $BFR{\geq}250mL/min$ (p = 0.042, log-rank). In the multi-variate Cox regression analyses, patients with BFR < 250 mL/min had higher all-cause mortality than those with $BFR{\geq}250mL/min$ (hazard ratio, 1.66; 95% confidence interval, 1.00 to 2.73; p = 0.048). Conclusions: Our data showed that BFR < 250 mL/min during HD was associated with higher all-cause mortality in chronic HD patients.