Expanded Hemodialysis with Theranova Dialyzer and Residual Kidney Function in Incident Hemodialysis Patients

Expanded hemodialysis (HD) using a medium cut-off dialyzer improves the clearance of middle-molecular toxins compared to conventional HD. This study evaluated the effect of expanded HD on preserving residual kidney function in incident HD patients. Patients who initiated HD 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 glomerular filtration rate (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. A total of 80 HD patients (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, -0.5] mL/min/1.73 m2). Theranova maintained greater 24-hour urine volume until 9 months, not at 12 months, compared to the high-flux dialyzer. The reduction ratio for κ/λ free light chains, TNF-α, and GDF-15 was higher in the Theranova group than in the high-flux group. The increase in the kidney injury marker, IGFBP7, was attenuated in the Theranova group. Hospitalization rate and mortality did not differ between the two groups. This trial suggests that expanded HD using the Theranova dialyzer may slow decline in residual kidney function compared with a high-flux dialyzer in incident HD patients.