Effect of hemodiafiltration or hemofiltration compared with hemodialysis on mortality and cardiovascular disease in chronic kidney failure: a systematic review and meta-analysis of randomized trials

Background: Whether convective modalities of dialysis, including hemofiltration (HF) and hemodiafiltration (HDF), improve cardiovascular outcomes and mortality is unclear.

Study design: Systematic review and meta-analysis.

Setting & population: Patients receiving HDF, HF, or standard hemodialysis (HD).

Selection criteria for studies: Randomized controlled trials.

Intervention: Convective modalities of dialysis (HDF and HF) versus standard HD.

Outcomes: The primary outcome was clinical cardiovascular outcomes. Secondary outcomes were all-cause mortality, episodes of symptomatic hypotension, dialysis adequacy, and β2-microglobulin level. Relative risks (RRs) or weighted mean differences with 95% CIs for individual trials were pooled using random-effects models.

Results: The search yielded 16 trials including 3,220 patients. Therapies assessed were convective modalities (HDF or HF) compared with standard HD. Compared with HD, convective modalities did not significantly reduce the risk of cardiovascular events (RR, 0.85; 95% CI, 0.66-1.10) or all-cause mortality (RR, 0.83; 95% CI, 0.65-1.05). Convective modalities reduced symptomatic hypotension (RR, 0.49; 95% CI, 0.30-0.81) and improved serum β2-microglobulin levels (-5.95 mg/L; 95% CI, -10.27 to -1.64), but had no impact on small-molecule clearance (weighted mean difference in Kt/V, 0.04; 95% CI, -0.04 to 0.12). There was a nonsignificant trend to a greater likelihood of receiving a kidney transplant for participants allocated to filtration therapies (RR, 1.19; 95% CI, 0.99-1.42).

Limitations: The trials were predominantly of suboptimal quality and underpowered, with imbalance in some prognostic variables at baseline. Intention-to-treat analysis was not used in some trials. Our analysis was limited to published outcomes.

Conclusions: The potential benefits of convective modalities over standard HD for cardiovascular outcomes and mortality remain unproved. Further high-quality randomized trials are needed to define the impact of these modalities on clinically important outcomes.