Expanded Hemodialysis with Theranova Dialyzer and Residual Kidney Function in Patients Starting Long-Term Hemodialysis

Key Points This randomized controlled trial evaluated the effect of expanded hemodialysis on preserving residual kidney function in patients starting treatment with long-term hemodialysis. The expanded hemodialysis group with Theranova dialyzer showed smaller decrease in GFR than the high-flux group over 12 months. The Theranova group had a larger reduction in middle molecules and inflammatory cytokines and smaller increases in kidney injury markers. Background Expanded hemodialysis using a medium cutoff dialyzer improves the clearance of middle-molecular toxins compared with conventional hemodialysis. This study evaluated the effect of expanded hemodialysis on preserving residual kidney function in patients starting treatment with long-term hemodialysis. Methods Patients who initiated long-term hemodialysis were randomized to receive dialysis with either a Theranova 400 (Baxter) or a high-flux dialyzer with a similar surface area over 12 months. The primary outcome was a change in GFR over 12 months, as determined by the mean of urea and creatinine clearance. The secondary outcome was a change in 24-hour urine volume, middle molecules, and kidney injury markers. Results A total of 80 patients on hemodialysis (mean age [SD]: 63 [12] years; male: 52 [65%]) underwent randomization. Over 12 months, the Theranova group demonstrated a significantly smaller decrease in GFR than the high-flux group (least squares mean difference of change [95% confidence interval], −1.4 [−2.4 to −0.5] ml/min per 1.73 m 2 ). Theranova maintained greater 24-hour urine volume until 9 months, not at 12 months, compared with the high-flux dialyzer. The reduction ratio for κ/λ free light chains, TNF- α , and growth differentiation factor-15 was higher in the Theranova group than in the high-flux group. The increase in the kidney injury marker, IGF-binding protein 7, was attenuated in the Theranova group. Hospitalization rate and mortality did not differ between the two groups. Conclusions This trial suggests that expanded hemodialysis using the Theranova dialyzer slowed decline in residual kidney function compared with a high-flux dialyzer in patients starting treatment with long-term hemodialysis. Clinical Trial registry name and registration number: Theranova versus High-flux Dialyzer on Preservation of Residual Renal Function, NCT04211571.