A comparison of early versus late initiation of renal replacement therapy for acute kidney injury in critically ill patients: an updated systematic review and meta-analysis of randomized controlled trials.

Background: To investigate the impact of timing the initiation of renal replacement therapy (RRT) on clinical outcomes in critically ill patients with acute kidney injury (AKI), focusing on the randomized controlled trials (RCTs) in this field.

Methods: The PubMed, EMBASE and Cochrane databases were searched between January 1, 1985, and June 30, 2016, to identify randomized trials that assessed the timing of initiation of RRT in patients with AKI.

Results: Nine RCTs, with a total of 1636 patients, were enrolled in this meta-analysis. A pooled analysis of the studies indicated no mortality benefit with "early" RRT, with an RR of 0.98 (95% CI 0.78 to 1.23, P = 0.84). There was no significant difference in intensive care unit (ICU) length of stay (LOS) or hospital LOS between the early and late RRT groups for survivors or nonsurvivors. Pooled analysis also demonstrated no significant change in renal function recovery (RR 1.02, 95% CI 0.88 to 1.19, I2 = 59%), RRT dependence (RR 0.76, 95% CI 0.42 to 1.37, I2 = 0%), duration of RRT (Mean difference 1.43, 95% CI -1.75 to 4.61, I2 = 78%), renal recovery time (Mean difference 0.73, 95% CI -2.09 to 3.56, I2 = 70%) or mechanical ventilation time (Mean difference - 0.95, 95% CI -3.54 to 1.64, I2 = 64%) between the early and late RRT groups. We found no significant differences in complications between the groups.

Conclusions: Our meta-analysis revealed that the "early" initiation of RRT in critically ill patients did not result in reduced mortality. Pooled analysis of secondary outcomes also showed no significant difference between the early and late RRT groups. More well-designed and large-scale trials are expected to confirm the result of this meta-analysis.