Is hemodiafiltration superior to high-flow hemodialysis in reducing all-cause and cardiovascular mortality in kidney failure patients? A meta-analysis of randomized controlled trials

IntroductionHemodiafiltration (HDF) and high-flux hemodialysis (hf-HD) are different methods of kidney replacement therapy (KRT) used for the treatment of kidney failure patients. A debate has raged over the last decade about the survival benefit of patients with the use of HDF compared with hf-HD, but with divergent results from randomized controlled trials. Therefore, this study aimed to perform a meta-analysis to compare HDF and hf-HD regarding all-cause and cardiovascular mortality.MethodsPubMed and Cochrane databases were searched until July 19, 2023, for randomized clinical trials comparing HDF and hf-HD in patients on maintenance dialysis. A meta-analysis was performed using Stata 16.1, applying fixed or random effect models according to the heterogeneity between studies.FindingsOf the 496 studies found, five met the inclusion criteria. Compared with the hf-HD group, the risk ratio (RR) for all-cause mortality with HDF use was 0.76 (95% CI: 0.67-0.88, I2 = 0%). HDF was associated with lower cardiovascular mortality, although the sensitivity analysis showed that the result differed between scenarios. Subgroup analysis showed lower all-cause mortality among patients without diabetes in the HDF group compared with hf-HD (RR 0.66, 95% CI: 0.51-0.81, I2 = 0%), but not in diabetic patients (RR = 0.89, 95% CI: 0.65-1.12, I2 = 0.0%). A subgroup analysis considering convection volumes was not performed, but the studies with the highest weight in the meta-analysis described convection volume as more than 20 L/session.DiscussionMore clinical studies considering critical risk factors, such as advanced age and preexisting cardiovascular disease, are needed to confirm the supremacy of HDF over hf-HD on the survival of patients treated by these two forms of kidney replacement therapy.