Long term variation of serum levels of uremic toxins in patients treated by post-dilution high volume on-line hemodiafiltration in comparison to standard low-flux bicarbonate dialysis: results from the REDERT study.
OBJECTIVE
Little information have been provided till now regarding the effect of high volume HDF (hv-OL-HDF) in respect to standard bicarbonate dialysis (BHD) in medium-long term protein-bound toxins removal.


METHODS
A randomised cross-over multicentre study (REDERT study) was designed to compare the effects of hv-OL-HDF and low-flux BHD on uremic toxins serum levels in 36 chronic dialysis patients followed for 13 months. Group 1 patients were treated with BHD (Treatment A) for 6 months, and afterwards, they were transferred to hv-OL-HDF for a further 6 months (Treatment B). Group 2 patients were treated with Treatment B for 6 months, and afterwards, they were transferred to Treatment A for a further 6 months. Total and free pre-dialysis indoxyl-sulfate (IS) and p-cresyl-sulfate (pCS) were determined starting a midweek dialysis session at baseline and after six months of hv-OL-HDF or BHD. IS and pCS, were simultaneously measured, by liquid chromatography/electrospray ionization-tandem mass spectrometry, Kt/v and pre and post-dialysis b-2microglobulin (b2MG) levels were measured every three months.


RESULTS
Kt/V was significantly increased in hv-OL-HDF (from 1.47 ± 0.24 to 1.49 ± 0.16; p < 0.01) and was reduced in BHD (from 1.51 ± 0.2 to 1.36 ± 0.21; p < 0.001). The mean infusion volume in HDF was 20.9 ± 2.1 L with a mean total convective volume of 23.8 ± 2.3 L and a significant removal of b2MG was obtained in hv-OL-HDF at month 3 and month 6. Both free and total levels of IS and pCS were significantly reduced in hv-OL-HDF at month 6 in respect to BHD.


CONCLUSIONS
In the present study we confirm the assumption that post-HDF is an effective technique in small and protein-bound uremic toxins removal.


BACKGROUND
Nephrology and Dialysis USL Nord Ovest Toscana, Versilia Hospital, Toscana, Italy. vincenzo.panichi@uslnordovest.toscana.it.
Vincenzo
http://orcid.org/0000-0002-5003-3172
V
Panichi
Department of Emergency and Organ Transplantation, Section of Nephrology, University of Bari 'Aldo Moro', Bari, Italy.
Maria Teresa
MT
Rocchetti
Nephrology and Dialysis USL Nord Ovest Toscana, Versilia Hospital, Toscana, Italy.
Alessia
A
Scatena
Nephrology and Dialysis USL Centro Toscana, Toscana, Italy.
Alberto
A
Rosati
Nephrology and Dialysis USL Nord Ovest Toscana, Versilia Hospital, Toscana, Italy.
Massimiliano
M
Migliori
Nephrology and Dialysis USL Centro Toscana, Toscana, Italy.
Francesco
F
Pizzarelli
Department of Emergency and Organ Transplantation, Section of Nephrology, University of Bari 'Aldo Moro', Bari, Italy.
Loreto
L
Gesualdo
D000368:Aged; D000369:Aged, 80 and over; D001639:Bicarbonates / Q000008:administration & dosage* / Q000009:adverse effects; D015415:Biomarkers / Q000097:blood; D002853:Chromatography, Liquid; D003408:Cresols / Q000097:blood*; D018592:Cross-Over Studies; D015314:Dialysis Solutions / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D017583:Hemodiafiltration / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D007200:Indican / Q000097:blood*; D007558:Italy; D008297:Male; D008875:Middle Aged; D021241:Spectrometry, Mass, Electrospray Ionization; D013463:Sulfuric Acid Esters / Q000097:blood*; D053719:Tandem Mass Spectrometry; D013997:Time Factors; D016896:Treatment Outcome; D014511:Uremia / Q000097:blood / Q000175:diagnosis / Q000628:therapy*; D001613:beta 2-Microglobulin / Q000097:blood
D001639:Bicarbonates; D015415:Biomarkers; D003408:Cresols; D015314:Dialysis Solutions; D013463:Sulfuric Acid Esters; D001613:beta 2-Microglobulin; C408690:4-cresol sulfate; D007200:Indican
Hemodialysis; Indoxil sulphate; Uremic toxins; p-cresol