Effect of Expanded Hemodialysis with Theranova Dialyzer on Preservation of Residual Kidney Function in Incident Hemodialysis Patients: THREAD Randomized Controlled Trial

Background: Expanded hemodialysis (HDx) using a medium cut-off dialyzer can improve the clearance of middle-molecular uremic toxins compared to conventional hemodialysis (HD). However, its effect on residual kidney function (RKF) remains unclear. This study evaluated the effect of HDx on preserving RKF in incident HD patients. Methods: Patients who initiated HD were randomized to receive dialysis with either an HDx with Theranova 400 or a high-flux (HF) dialyzer with a similar surface area over 12 months. The primary outcome was a change of glomerular filtration rate (GFR) over 12 months, as determined by the average 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 HD patients (mean age: 62.7±11.9 years; male: 52 [65.0%]) underwent randomization. During 12 months, the Theranova group demonstrated a significantly smaller decrease in GFR than the HF group (−1.20 [IQR, −2.29, −0.22] mL/min/1.73m2 vs. −2.24 [IQR, −3.62, −0.46] mL/min/1.73m2, P=0.019) (Fig 1). No significant difference in 24-hour urine volume was observed at 12-month, whereas Theranova maintained greater 24-hour urine volume until 9-month compared to the HF dialyzer. After 12 months, the Theranova group showed a significantly lower increase in β2-microglobulin. The increase in kidney injury markers such as IGFBP-7 and KIM-1 was significantly reduced in the Theranova group compared to the HF group. The reduction ratio for κ/λ free light chains, TNF-α. and GDF-15 was higher in the Theranova group than the HF group. There were no differences in hospitalization rate or mortality between the two groups. Conclusion: HDx using the Theranova dialyzer has preserved the decline in RKF compared to the HF dialyzer of similar size in newly initiated HD patients. Funding: Commercial Support - Baxter