Randomized Trial of Twice-Weekly Versus Thrice-Weekly Hemodiafiltration for Initiation of Renal Replacement Therapy

This study presents the first randomized controlled trial (RCT) comparing incremental hemodiafiltration (HDF) (i-HDF), beginning with twice-weekly sessions, to conventional thrice-weekly HDF (c-HDF) in incident dialysis patients with preserved residual kidney function (RKF): urea clearance (KrU) ≥ 2.5 ml/min.

In this multicenter, open-label trial, 150 patients were randomized 1:1 to either i-HDF (n = 77) or c-HDF (n = 73), regardless of comorbidity burden. The primary outcome was the decline in glomerular filtration rate (GFR) over 12 months. Secondary outcomes included changes in RKF (measured by 24-hour urine output, KrU, and creatinine clearance [KrCr]), incidence of anuria, hospital admissions, mortality, quality of life (using the Kidney Disease Quality of Life-36), and the total number of HDF sessions.

No significant differences were found between groups in GFR decline, RKF parameters, or clinical outcomes such as hospitalizations, mortality, or anuria (5 cases in i-HDF vs. 4 in c-HDF). At 6 months, the i-HDF group reported slight improvements in quality of life, particularly in disease burden domains, though these gains diminished by 12 months. Fifteen patients in the i-HDF group transitioned to thrice-weekly HDF after an average of 193 days, and none refused the increase in frequency when indicated. The i-HDF group received significantly fewer dialysis sessions annually (69.1 vs. 122.6).

Incremental HDF is a safe and effective option for patients with preserved RKF, offering similar clinical outcomes to conventional schedules, with modest short-term quality-of-life benefits and substantial resource savings. Further trials are needed to validate these findings and assess patient preferences and cost-effectiveness.