[Anti convection: convective therapies aren't the future of extracorporeal blood purification]

Despite technological advances in dialysis therapies and modalities, the mortality and morbidity among patients on hemodialysis (HD) are still high. Membrane permeability, convection techniques, and the number and duration of dialysis sessions have been considered as being potentially related to patient outcome. The available data from 2 randomized controlled clinical trials suggest that treatment with high-flux membranes does not significantly reduce all-cause mortality in kidney patients. However, subgroups of patients such as diabetics, malnourished patients and patients with >3.7 years of dialysis could have a greater survival advantage with high-flux membranes. Interest in alternative hemodialysis regimens has grown substantially during the past decade. Delivered as either daily (1.5 to 2.5 h, 6 d/wk) or nocturnal (6 to 8 h, 6 d/wk) treatment, alternative HD has shown promising results with better control of blood pressure, reduction of left ventricular hypertrophy, and easier control of phosphate metabolism. Elderly patients, patients with heart disease and those with vascular instability during HD could benefit from daily regimens. If well motivated, young patients may improve their dialysis efficiency, nutritional status and work capacity mainly with long nocturnal HD while waiting for a kidney transplant. However, before significant resources are invested in initiating alternative hemodialysis programs, further data on mortality and cardiovascular morbidity, preferably from randomized clinical trials, are required.