Stepwise Incremental Hemodialysis and Low-Protein Diet Supplemented with Keto-Analogues Preserve Residual Kidney Function: A Randomized Controlled Trial

<b>Background:</b> Rapid loss of residual kidney function (RKF) is associated with unfavorable outcomes. We conducted an RCT to compare the effects on RKF preservation of incremental HD between once-weekly HD (1-WHD) and twice-weekly HD (2-WHD). <b>Methods:</b> ESKD patients with an eGFR of 5-10 mL/min/1.73 m² and urine output of ≥800 mL/day were randomly assigned to receive either once-weekly HD (1-WHD) or twice-weekly HD (2-WHD) for 12 months. Patients in the 1-WHD group were prescribed once-weekly HD combined with low-protein diet (0.6 g/kg/day) supplemented with keto-analogues (KAs) 0.12 g/kg/day. In the 2-WHD group, patients received twice-weekly HD with a regular-protein diet. Primary outcomes were changes in RKF by renal clearance and urine volume. Nutritional status, muscle parameters, and quality of life (QoL) were also assessed. <b>Results:</b> A total of 30 incident HD patients were randomized. Baseline RKF, urine volume, and demographic were not different between groups. After 3 months, urine volume was significantly higher in the 1-WHD group than in the 2-WHD group (1921 ± 767 mL/day vs. 1305 ± 599 mL/day, <i>p</i> = 0.02), and these significant findings persisted throughout the entire study period. For RKF, 1-WHD also had a lesser decline in urinary urea (CUrea) and creatinine clearance (CCr) than 2-WHD, with statistically significant differences observed from months 6-12. By month 6, the 1-WHD group exhibited significantly higher CUrea and CCr compared to the 2-WHD group, with CUrea at 3.2 ± 2.3 vs. 1.7 ± 1.0 mL/min (<i>p</i> = 0.03) and CCr at 5.9 ± 3.6 vs. 3.8 ± 1.4 mL/min (<i>p</i> = 0.04), respectively. Serum albumin levels, skeletal muscle mass, anemia status, metabolic parameters, protein-bound uremic toxins, and QoL scores were comparable between the two groups. <b>Conclusions:</b> Incremental HD, starting with once-weekly HD combined with protein restriction supplemented with KAs, appears to better preserve RKF among incident HD patients compared to twice-weekly HD with a regular-protein diet. This HD regimen was also associated with safety in metabolic and nutritional profiles.