Intensities of renal replacement therapy in acute kidney injury: a systematic review and meta-analysis.

BACKGROUND AND OBJECTIVES Clinical trials of the intensity of renal replacement therapy (RRT) for people with acute kidney injury (AKI) have produced conflicting results. A systematic review and meta-analysis was undertaken to assess the effect of different intensities of RRT on all-cause mortality and renal recovery in AKI patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS MEDLINE, EMBASE, and the Cochrane Library database were systematically searched for trials published between 1950 and 2009. Inclusion criteria were completed, prospective, adult-population, randomized controlled studies. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated. Summary estimates of RR were obtained using a random effects model. Heterogeneity, metaregression, publication bias, and subgroup analyses were conducted. RESULTS Eight trials were identified that provided data on 3841 patients and 1808 deaths. More intense RRT (35 to 48 ml/kg per h or equivalent) had no overall effect on the risk of death (RR 0.89, 95% CI 0.76 to 1.04, P = 0.143) or recovery of renal function (RR 1.12, 95% CI 0.95 to 1.31, P = 0.181) compared with less-intensive regimens (20 to 25 ml/kg per h or equivalent). Significant heterogeneity was identified with contributing factors including publication year (P = 0.004) and Jadad score (P = 0.048). CONCLUSIONS Within the intensity ranges studied, higher intensity RRT does not reduce mortality rates or improve renal recovery among patients with AKI. The results do not negate the importance of RRT intensity in the treatment of AKI patients but rather reinforce the need to better understand the effects of treatment modalities, doses, and timing in this varied, high-risk population.