TEN-YEAR EXPERIENCE OF INCREMENTAL HEMODIAFILTRATION: LONG-TERM OUTCOMES FROM A SINGLE-CENTER COHORT

Incremental hemodialysis, initiated as once- or twice-weekly HD, provides a gradual transition to dialysis in patients with end-stage kidney disease (ESKD). It has been shown to be safe in patients with adequate residual kidney function (RKF) and may help preserve residual kidney function. However, long-term outcomes remain uncertain, as mortality after HD initiation remains high. Data from national cohorts have shown survival rates of less than 90% in the first year and below 60% at five years. This study aims to evaluate the long-term outcomes of patients who initiated HD with an incremental hemodiafiltration protocol.

This retrospective cohort study included 44 incident end-satge kidney disease (ESKD) patients who received incremental HDF between 2016 and 2025 at King Chulalongkorn Memorial Hospital, Thailand. Eligibility criteria for incremental HDF included preserved RKF defined as renal urea clearance ≥ 3 mL/min and 24-hour urine volume ≥ 800 mL/day for once-weekly HDF or ≥ 500 mL/day for twice-weekly HDF, along with stable electrolyte and volume status and absence of malnutrition. The HDF protocol utilized online HDF with a biocompatible high-flux dialyzer and ultrapure water. RKF, 24-hour urine volume, dialysis adequacy, and clinical status were monitored monthly. The dialysis frequency was increased if patients experienced a decline in RKF or no longer met eligibility criteria. Survival analysis was performed for overall mortality, and death- and transplant-censored time to transition to higher HD frequency.

Among 44 patients, 22 (50%) were in once weekly HDF and 22 (50%) were in twice weekly HDF. The mean age was 68.8 ± 14.9years and the median follow-up time of 45.9 (range 8.5-108.6) months. Mean baseline RKF was 6.3 ± 2.6 mL/min and mean baseline urine volume was 1722 ± 640 mL. During the study period, there were 9 kidney transplantations and 7 deaths. Overall survival was 97.7% at 1 year, 92.4% at 3 years, and 80.9% at 5 years. Overall survival rates were 97.7% at 1 year, 92.4% at 3 years, and 80.9% at 5 years. There was no significant difference in survival between the once-weekly and twice-weekly groups (log-rank p = 0.66).

The median time to increase HD frequency was 207 days in once-weekly HDF group and 1440 days in twice-weekly HDF group. After 1 year, 25% of patients receiving once-weekly HDF and 82% of those receiving twice-weekly HDF maintained a dialysis frequency of fewer than three sessions per week. After 1 year, RKF declined to 3.00 ± 2.10 mL/min and urine volume to 1126.60 ±  478.72 mL. The major reasons for step-up were decreased RKF (40.9%) and volume overload (20.5%). Other reasons included intradialytic hypotension (6.8%) and high interdialytic weight gain (6.8%).

Table Baseline Characteristics of incremental HDF cohort

Incremental HDF demonstrated excellent long-term survival in this cohort, comparable to previously reported outcomes in traditional hemodialysis. Incremental HDF may be considered as an initial dialysis modality for incident HD patients, particularly those with preserved RKF. Close monitoring of RKF, urine volume, and regular assessment of dialysis adequacy are essential keys to ensure successful and sustained incremental HDF.