Background: Standard low-flux haemodialysis (HD) is not very efficacious, and patient morbidity and mortality rates are still very high. According to the initial study design, the MPO study reported that high-flux HD (hf-HD) showed a significant 37% relative risk reduction of mortality in patients with serum albumin ≤4 g/dl; online haemodiafiltration (HDF) is considered the most efficient technique of using high-flux membranes, as clearances of small solutes, like urea, are higher than in haemofiltration and clearances of middle solutes, like β2-microglobulin, are higher than in hf-HD. Summary: Three randomized trials have recently been published analysing the effect of online HDF on mortality. Two trials were unable to demonstrate a positive effect of HDF on survival, while 1 showed a significantly better survival in patients randomized to HDF in comparison to those randomized to hf-HD. It is intriguing that post hoc analyses of these 3 studies showed that the patients randomized to online HDF who received the highest convection volumes had a lower risk of mortality and cardiovascular events than those randomized to HD. Four very recently published meta-analyses have shown inconsistent results concerning the effect of convective treatments in improving patient general and cardiovascular survival, while they have consistently shown a significant reduction of the intradialytic symptomatic hypotension in patients treated with convective techniques in comparison with those treated with prevalent diffusive ones. Key Messages: The results of the randomized trials on the effect of HDF in improving patient survival are inconclusive. Moreover, trials specifically designed for testing the effect of increased convection of online HDF on patient survival and morbidity in comparison to patients treated with hf-HD are still awaited.

1.
Von Albertini B, Miller JH, Gardner PW, et al: High-flux haemodiafiltration: under six hours/week treatment. Trans Am Soc Artif Intern Organs 1984;30:227-231.
[PubMed]
2.
Del Vecchio L, Locatelli, F, Carini M: What we know about oxidative stress in patients with chronic kidney disease on dialysis: clinical effects, potential treatment, and prevention. Semin Dial 2011;24:56-64.
[PubMed]
3.
Eknoyan G, Beck GJ, Cheung AK, et al: Effect of dialysis dose and membrane flux in maintenance haemodialysis. N Engl J Med 2002;347:2010-2019.
[PubMed]
4.
Cheung AK, Levin NW, Greene T, et al: Effects of high-flux haemodialysis on clinical outcomes: results of the HEMO study. J Am Soc Nephrol 2003;14:3251-3263.
[PubMed]
5.
Locatelli F, Martin-Malo A, Hannedouche T, et al: Effect of membrane permeability on survival of haemodialysis patients. J Am Soc Nephrol 2009;20:645-654.
[PubMed]
6.
Cheung AK, Rocco MV, Yan G, et al: Serum beta-2 microglobulin levels predict mortality in dialysis patients: results of the HEMO study. J Am Soc Nephrol 2006;17:546-555.
[PubMed]
7.
Tattersall J, Martin-Malo A, Pedrini L, et al: EBPG guideline on dialysis strategies. Nephrol Dial Transplant 2007;22:ii5-ii21.
[PubMed]
8.
Locatelli F, Mastrangelo F, Redaelli B, et al: Effects of different membranes and dialysis technologies on patient treatment tolerance and nutritional parameters. The Italian Cooperative Dialysis Study Group. Kidney Int 1996;50:1293-1302.
[PubMed]
9.
Penne EL, van der Weerd NC, van der Dorpel MA, et al: Short-term effects of on-line haemodiafiltration on phosphate control: a result from the randomized controlled Convective Transport Study (CONTRAST). Am J Kidney Dis 2010;55:77-87.
[PubMed]
10.
Locatelli F, Altieri P, Andrulli S, et al: Phosphate levels in patients treated with low-flux haemodialysis, predilution haemofiltration and haemodiafiltration: post hoc analysis of a multicentre, randomized and controlled trial. Nephrol Dial Transplant 2014;29:1239-1246.
[PubMed]
11.
Pedrini L, De Cristofaro V, Comelli M, et al: Long-term effects of high-efficiency on-line haemodiafiltration on uraemic toxicity. A multicentre prospective randomized study. Nephrol Dial Transplant 2011;26:2617-2624.
[PubMed]
12.
Movilli E, Camerini C, Gaggia P, et al: Effect of post-dilutional on-line haemodiafiltration on serum calcium, phosphate and parathyroid hormone concentrations in uraemic patients. Nephrol Dial Transplant 2011;26:4032-4037.
[PubMed]
13.
Locatelli F, Altieri P, Andrulli S, et al: Predictors of haemoglobin levels and resistance to erythropoiesis-stimulating agents in patients treated with low-flux haemodialysis, haemofiltration and haemodiafiltration: results of a multicenter randomized and controlled trial. Nephrol Dial Transplant 2012;27:3594-3600.
[PubMed]
14.
Panichi V, Scatena A, Rosati A, et al: High-volume online haemodiafiltration improves erythropoiesis-stimulating agent (ESA) resistance in comparison with low-flux bicarbonate dialysis: results of the REDERT study. Nephrol Dial Transplant 2015;30:682-689.
[PubMed]
15.
Locatelli F, Marcelli D, Conte F, et al: Comparison of mortality in ESRD patients on convective and diffusive extracorporeal treatments. The Registro Lombardo Dialisi e Trapianto. Kidney Int 1999;55:286-293.
[PubMed]
16.
Wizemann V, Lotz C, Techert F, et al: On-line haemodiafiltration versus low-flux haemodialysis: a prospective randomized study. Nephrol Dial Transplant 2000;15(suppl 1): 43-48.
[PubMed]
17.
Lin CL, Huang CC, Chang CT, et al: Clinical improvement by increased frequency of on-line haemodiafiltration. Ren Fail 2001;23:193-206.
[PubMed]
18.
Maduell F, del Pozo C, Garcia H, et al: Change from conventional haemodiafiltration to on-line haemodiafiltration. Nephrol Dial Transplant 1999;14:1202-1207.
[PubMed]
19.
Maggiore Q, Pizzarelli F, Sisca S, et al: Blood temperature and vascular stability during haemodialysis and hemofiltration. Trans Am Soc Artif Intern Organs 1982;28:523-537.
[PubMed]
20.
Donauer J, Schweiger C, Rumberger B, et al: Reduction of hypotensive side effects during online-haemodiafiltration and low temperature haemodialysis. Nephrol Dial Transplant 2003;18:1616-1622.
[PubMed]
21.
Locatelli F, Altieri P, Andrulli S, et al: Hemofiltration and haemodiafiltration reduce intradialytic hypotension in ESRD. J Am Soc Nephrol 2010;21:1798-1807.
[PubMed]
22.
Maduell F, Moreso F, Pons M, et al: High-efficiency postdilution online hemodiafiltration reduces all-cause mortality in hemodialysis patients. J Am Soc Nephrol 2013;24:487-498.
[PubMed]
23.
Ok E, Asci G, Toz H, et al: Mortality and cardiovascular events in online haemodiafiltration (OL-HDF) compared with high-flux dialysis: results from the Turkish OL-HDF. Nephrol Dial Transplant 2013;28:192-202.
[PubMed]
24.
Grootemann M, Van den Dorpel MA, Bots ML, et al: Effect of online hemodiafiltration on all-cause mortality and cardiovascular outcomes. J Am Soc Nephrol 2012;23:1087-1096.
[PubMed]
25.
Locatelli F, Horl WH: A step towards making online hemodiafiltration a gold standard. Nat Rev Nephrol 2013;9:316-318.
[PubMed]
26.
Wang AY, Ninomiya T, Al-Kahwa A, et al: Effect of hemodiafiltration or hemofiltration compared with hemodialysis on mortality and cardiovascular disease in chronic kidney failure: a systematic review and meta-analysis of randomized trials. Am J Kidney Dis 2014;63:968-978.
[PubMed]
27.
Nistor I, Palmer SC, Craig JC, et al: Convective versus diffusive dialysis therapies for chronic kidney failure: an updated systematic review of randomized controlled trials. Am J Kidney Dis 2014;63:654-667.
[PubMed]
28.
Susantitaphong P, Siribamrungwong M, Jaber BL, et al: Convective therapies versus low-flux hemodialysis for chronic kidney failure: a meta-analysis of randomized controlled trials. Nephrol Dial Transplant 2013;28:2859-2874.
[PubMed]
29.
Mostovaya IM, Blankestijn PJ, Bots ML, et al: Clinical evidence on hemodiafiltration: a systematic review and a meta-analysis. Semin Dial 2014;27:119-127.
[PubMed]
30.
Altieri P, Sorba G, Bolasco P, et al; Sardinian Study Group on Hemofiltration On-Line: Comparison between hemofiltration and hemodiafiltration in a long-term prospective cross-over study. J Nephrol 2004;17:414-422.
[PubMed]
31.
Schiffl H: Prospective randomized cross-over long-term comparison of online haemodiafiltration and ultrapure high-flux haemodialysis. Eur J Med Res 2007;12:26-33.
[PubMed]
You do not currently have access to this content.