Acute renal failure in the intensive care unit: A systematic review of the impact of dialytic modality on mortality and renal recovery

Background: There is controversy about which dialytic modality should be used for the treatment of acute renal failure (ARF) in the intensive care unit. We performed a systematic review and meta-analysis to determine the relative risks (RRs) of mortality and renal recovery associated with intermittent hemodialysis (IHD) therapy compared with continuous renal replacement therapy (CRRT) in critically ill adults with ARF. Methods: Four databases (MEDLINE, Cochrane Library, Database of Abstracts and Reviews, and Science Citation Index), hand searching of conference proceedings and journals, manual review of bibliographies from identified articles, and contact with experts were used. All randomized trials (published or unpublished in any language) that compared mortality between intermittent and continuous treatments were eligible. Trials for which an RR for mortality could not be calculated or with multiple experimental interventions were excluded. Data were extracted separately by two authors and recorded on a standardized form. Disagreements were resolved by consensus. Results: Six eligible trials were identified; four of these provided data on renal outcomes. RR (mortality) for IHD was 0.96 (95% confidence interval [CI], 0.85 to 1.08; P = 0.50), RR (renal death) was 1.02 (95% CI, 0.89 to 1.17; P = 0.78), and RR (dialysis dependence) in survivors was 1.19 (95% CI, 0.62 to 2.27; P = 0.60; all compared with continuous therapy). Several sensitivity analyses did not change these results. Of the outcomes studied, the risk for dialysis dependence in survivors would be most sensitive to the addition of new trials. Conclusions: In comparison to IHD therapy, CRRT does not improve survival or renal recovery in unselected critically ill patients with ARF. Future studies should focus on well-defined subgroups of such patients using lessons learned from the trials in this meta-analysis. The high cost of chronic dialysis therapy and the relative instability of the RR for dialysis dependence suggest that future trials also should evaluate differences in renal recovery between dialytic modalities.