- Design
- Randomised, multicentre crossover trial
- Population
- 21 children on maintenance dialysis, median age 15
- Primary outcome
- Reduction in α1-microglobulin
- Effect
- Pre-dialysis α1-microglobulin −17.0 ng/mL (95% CI −27.0 to −3.5) with pre-HDF
This multicentre randomised crossover trial compared four weeks of pre-filter and four weeks of post-filter haemodiafiltration (HDF) in 24 children on maintenance dialysis; 21 completed (median age 15). All other dialysis settings were kept the same.
Pre-filter HDF achieved much higher convection volumes (36.2 vs 14.3 L/m² per session). Pre-dialysis α1-microglobulin, β2-microglobulin and myoglobin were lower, reduction ratios for protein-bound toxins such as indoxyl sulfate were higher, and inflammatory markers were lower. Small-solute clearance (Kt/V) and albumin did not differ. Diastolic blood pressure was higher with pre-filter HDF, associated with higher replacement volume and post-dialysis sodium.
It is a small, short, surrogate-outcome trial. But in children, where middle-molecule removal is linked to growth and cardiovascular health, pre-filter HDF is a reasonable option — with an eye on sodium and blood pressure.
- Consider pre-filter HDF in children needing greater middle-molecule clearance.
- Monitor blood pressure and post-dialysis sodium with high replacement volumes.
- Adjust dialysate sodium to offset sodium loading.
- Evidence is surrogate-based; long-term outcomes are unknown.
Why it matters
It offers a way to increase convection in children without compromising small-solute clearance.
Don't overread it
Twenty-one children for four weeks each, with laboratory endpoints — no clinical outcomes were measured.
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