Timing of Initiation of Renal Replacement Therapy in Acute Kidney Injury: A Systematic Review and Meta-analysis

Objective: The aim of the study is to summarize the effects of timing of initiation of renal replacement therapy (RRT) on mortality. Methods: A systematic search for randomized controlled trials (RCTs) and other clinical studies was performed without language restriction in PubMed, Web of Science, and Embase. We estimated pooled relative risk ratios (RRs) and 95% confidence intervals (CIs) using fixed effects model or random effects model as appropriate. Heterogeneity, publication bias, and subgroup analyses were conducted. Results: We analyzed the date extracted from 15 studies (3 RCTs, 2 prospective, and 10 retrospective comparative cohort studies) with a total of 2955 patients. Overall, 51.0% (772/1514) patients died in the "early" RRT group compared with 58.0% (836/1441) in the "late" RRT group. The pooled RR was 0.71 (95% CI: 0.59, 0.86), but the heterogeneity existed (p < 0.00001). Subgroup analysis based on modality did not record heterogeneity across trials. In continuous RRT (CRRT) group (n = 607), patients treated with "early" CRRT suggested a significant decrease in mortality compared with those in "late" CRRT group (27.8% vs. 43.0%) and the RR was 0.69 (95% CI: 0.56, 0.84) without evidence of heterogeneity (I-2 = 33%, p = 0.18). In intermittent hemodialysis (IHD) group (n = 115), the RR was 0.26 (95% CI: 0.15, 0.45) without evidence of heterogeneity (I-2 = 0%, p = 0.50). In the mixed group, heterogeneity existed. Conclusion: "Early" CRRT and "early" IHD both could reduce the mortality of patients with acute kidney injury compared with "late" CRRT or IHD.