M K TIONG1,2, N D TOUSSAINT1,2, E R SMITH1,2, C A HUTCHISON3, E M PASCOE4, E G RYAN4, C M HAWLEY4,5, R KRISHNASAMY4,6
1Department of Nephrology – The Royal Melbourne Hospital, Parkville, Australia, 2Department of Medicine (RMH) – University of Melbourne, Parkville, Australia, 3Department of Medicine – Hawke’s Bay Hospital, Hawke’s Bay, New Zealand, 4Australasian Kidney Trials Network – The University of Queensland, Brisbane, Australia, 5Department of Nephrology – Princess Alexandra Hospital, Brisbane, Australia, 6Department of Nephrology – Sunshine Coast University Hospital, Birtinya, Australia
Aim: To evaluate effects of a medium cut-off (MCO) dialyser on protein-bound solutes and mineral metabolism markers in the tRial Evaluating Mid cut-Off Value membrane clearance of Albumin and Light chains in HaemoDialysis patients (REMOVAL-HD) study.
Background: Regular use of MCO dialysers for haemodialysis (HD) may improve clearance of uraemic toxins, predominantly larger middle molecules. However, the impact of MCO dialysers on long-term clearance of various components of the uraemic milieu is unknown. We assessed changes of protein-bound uraemic toxins (total and free indoxyl sulphate [IS] and p-cresylsulphate [PCS]) and markers of mineral metabolism (intact fibroblast growth factor-23 [iFGF23], fetuin-A and endogenous calciprotein particles [CPP1 and CPP2]) over 6 months of MCO dialyser use in the REMOVAL-HD study.
Methods: Mid-week, pre-dialysis samples were collected for each analyte at baseline and after 12 and 24 weeks of MCO use in stable adult HD patients. Change from baseline to week 12 and 24 was calculated for each analyte, excluding participants with missing samples.
Results: 87 participants were studied, mean age 66.5±14.5yrs, 38% female, 51% diabetic, mean urine output 200ml/24hrs. iFGF23 was reduced at week 12 compared to baseline, with a sustained reduction at week 24 (iFGF23 [n=76] -22.1% [95%CI -36.9, -3.0], p=0.027). There was no significant change in IS, PCS, fetuin-A or CPP2 levels. Non-significant reduction in CPP1 was seen at 24 weeks (CPP1 [n=75] -18.1% [95%CI -34.9, 3.0], p=0.085).
Conclusions: Use of a MCO dialyser over 24 weeks was associated with a sustained reduction in FGF23, while other measured components of the uraemic milieu were not significantly altered. Further studies are required to determine whether the observed reduction in FGF23 is associated with improved patient outcomes.
Dr Mark Tiong completed his RACP fellowship in nephrology in 2019 and is currently undertaking his PhD in the area of CKD-MBD at The Royal Melbourne Hospital and The University of Melbourne. He is also interested in Aboriginal and Torres Strait Islander health, having previously worked for the Central Australian Health Service in Alice Springs, and is also a current member of the ANZDATA Aboriginal and Torres Strait Islander Health Working Group.