The Effect of On-line High-flux Hemofiltration Versus Low-flux Hemodialysis on Mortality in Chronic Kidney Failure: A Small Randomized Controlled Trial

Background

Given the paucity of prospective randomized controlled trials assessing comparative performances of different dialysis techniques, we compared on-line high-flux hemofiltration (HF) with ultrapure low-flux hemodialysis (HD), assessing survival and morbidity in patients with end-stage renal disease (ESRD).

Study Design

An investigator-driven, prospective, multicenter, 3-year-follow-up, centrally randomized study with no blinding and based on the intention-to-treat principle.

Setting & Participants

Prevalent patients with ESRD (age, 16 to 80 years; vintage > 6 months) receiving renal replacement therapy at 20 Italian dialysis centers.

Interventions

Patients were centrally randomly assigned to HD (n = 32) or HF (n = 32).

Outcomes & Measurements

All-cause mortality, hospitalization rate for any cause, prevalence of dialysis hypotension, standard biochemical indexes, and nutritional status. Analyses were performed using the multivariate analysis of variance and Cox proportional hazard method.

Results

There was significant improvement in survival with HF compared with HD (78%, HF versus 57%, HD) at 3 years of follow-up after allowing for the effects of age (P = 0.05). End-of-treatment Kt/V was significantly higher with HD (1.42 ± 0.06 versus 1.07 ± 0.06 with HF), whereas β₂-microglobulin levels remained constant in HD patients (33.90 ± 2.94 mg/dL at baseline and 36.90 ± 5.06 mg/dL at 3 years), but decreased significantly in HF patients (30.02 ± 3.54 mg/dL at baseline versus 23.9 ± 1.77 mg/dL; P < 0.05). The number of hospitalization events for each patient was not significantly different (2.36 ± 0.41 versus 1.94 ± 0.33 events), whereas length of stay proved to be significantly shorter in HF patients compared with HD patients (P < 0.001). End-of-treatment body mass index decreased in HD patients, but increased in HF patients. Throughout the study period, the difference in trends of intradialytic acute hypotension was statistically significant, with a clear decrease in HF (P = 0.03).

Limitations

This is a small preliminary intervention study with a high dropout rate and problematic generalizability.

Conclusion

On-line HF may improve survival independent of Kt/V in patients with ESRD, with a significant decrease in plasma β₂-microglobulin levels and increased body mass index. A larger study is required to confirm these results.

Index Words: Hemodialysis, hemofiltration, high flux, dialysis adequacy