Convective therapies versus low-flux hemodialysis for chronic kidney failure: a meta-analysis of randomized controlled trials

Background. Although convective therapies have gained popularity for the optimal removal of uremic solutes, their benefits and potential risks have not been fully elucidated. We conducted a meta-analysis of all randomized controlled trials comparing convective therapies with low-flux hemodialysis in patients with chronic kidney failure. We performed a literature search using MEDLINE (inception-December 2012), Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, scientific abstracts from meetings and bibliographies of retrieved articles. Randomized controlled trials comparing the effect of convective therapies including high-flux hemodialysis, hemofiltration or hemodiafiltration versus low-flux hemodialysis were included. Random-effects model meta-analyses were used to examine continuous and binary outcomes. Sixty-five (29 crossover and 36 parallel-arm) trials were identified (n 12 182). Convective therapies resulted in a decrease in all-cause mortality [relative risk (RR) 0.88; 95 confidence interval (CI) 0.76, 1.02, P 0.09], cardiovascular mortality (RR 0.84; 95 CI 0.71, 0.98, P 0.03), all-cause hospitalization (RR 0.91; 95 CI 0.82, 1.01; P 0.08) and therapy-related hypotension (RR 0.55, 95 CI 0.35, 0.87, P 0.01). Convective therapies also resulted in an increase in the clearance of several low-molecular-weight (urea, creatinine and phosphate), middle-sized (-2 microglobulin and leptin) and protein-bound (homocysteine, advanced glycation end-products and pentosidine) solutes and a decrease in inflammatory markers (interleukin-6). There was no impact of convective therapies on cardiac morphological and functional parameters, and blood pressure and anemia parameters. Although convective therapies are associated with improved clearance of uremic solutes, the potential long-term benefits of specific convective modalities require further study.