Extracorporeal RRT modalities: A systemic review

Abstract

Objective: Hemodialysis (HD), hemofiltration (HF), hemodiafiltration (HDF), and acetate free biofiltration (AFB) are renal replacement therapy (RRT) methods in which impurities are removed from the blood extracorporeally. It has been suggested that HF, HDF, and AFB may have fewer cardiovascular side‐effects than HD and may reduce incidence of dialysis‐related amyloid‐ associated complications due to more effective removal of β2‐microglobulin. Methods: We performed a systematic review of randomized controlled trials (RCTs) comparing these RRT modalities. Out of 1672 abstracts identified by searching MEDLINE, EMBASE, and Cochrane Controlled Trials Registry, 18 trials (588 patients) were included. Our comparisons were convective modalities (HF/HDF/AFB) vs HD (16 trials); HDF/AFB vs HF (no trials); and HDF vs AFB (2 trials). Data were extracted by two reviewers independently on mortality, hypotension episodes, dialysis sessions associated with “adverse symptoms”(headache, nausea, and vomiting), hospital admissions, adequacy of dialysis, number of patients with amyloid related complications, β2‐microglobulin removal, and quality of life (QOL). Results: No significant difference was found with regards to mortality, hospitalization, dialysis‐related hypotension, dialysis‐related symptoms, Kt/V, predialysis β2‐microglobulin values between convective modalities (HF/HDF/AFB) and HD, and HDF and AFB. Quality of life was assessed only in two studies comparing HF/HDF/AFB and HD. One study that used an unvalidated scoring tool showed that patients on convective modalities scored significantly better than those on HD; whereas, another study using a validated scoring system, the Kidney Diseases Questionnaire, failed to show significant differences between the two groups. Conclusions: While this review summarized the best available evidence, it is based on very few trials. The trials included in this review are small and are therefore inadequately powered to detect differences between effects of the relevant treatments. Overall, HF, HDF, and AFB have not been shown to have significant advantage over HD with regard to clinically important outcomes of mortality, dialysis‐related hypotension and manifestations of dialysis‐related amyloidosis, and therefore, it is not possible to recommend the use of one modality in preference to the other.