Early versus late initiation of renal replacement therapy impacts mortality in patients with acute kidney injury post cardiac surgery: a meta-analysis

Background: Acute kidney injury (AKI) is a common clinical complication of cardiac surgery and increases mortality and hospitalization. We aimed to explore and perform an updated meta-analysis of qualitative and quantitative evaluations of the relationship between early renal replacement therapy (RRT) and mortality. Methods: We searched the Chinese Biomedical Database, the Cochrane Library, EMBASE, Global Health, MEDLINE and PubMed. Results: Fifteen studies (five randomized controlled trials (RCTs), one prospective cohort and nine retrospective cohorts) including 1479 patients were identified for detailed evaluation. The meta-analysis suggested that early RRT initiation reduced 28-day mortality (odds ratio (OR) 0.36; 95% confidence interval (CI) 0.23 to 0.57; I-2 60%), and shortened intensive care unit (ICU) length of stay (LOS) (mean difference (MD) -2.50; 95% CI -3.53 to -1.47; I-2 88%) and hospital LOS (MD -0.69; 95% CI -1.13 to -0.25; I-2 88%), and also reduced the duration of RRT (MD -1.18; 95% CI -2.26 to -0.11; I-2 69%), especially when RRT was initiated early within 12 hours (OR 0.23; 95% CI 0.08 to 0.63; I-2 73%) and within 24 hours (OR 0.52; 95% CI 0.28 to 0.95; I-2 58%) in patients with AKI after cardiac surgery. Conclusions: Early RRT initiation decreased 28-day mortality, especially when it was started within 24 hours after cardiac surgery in patients with AKI.