Acute kidney injury and cardiac arrest in the modern era: an updated systematic review and meta-analysis

Objective: Acute kidney injury (AKI) is associated with higher morbidity and mortality in cardiac arrest (CA). There are limited contemporary data on the incidence and outcomes of AKI in CA.Methods: We comprehensively searched the databases of MEDLINE, EMBASE, PUBMED, and the Cochrane from inception to November 2020. Observational studies that reported the incidence of AKI in CA survivors were included. Data from each study were combined using the random effects to calculate pooled incidence and risk ratios with 95% confidence intervals (CIs). The primary outcome was short-term mortality and secondary outcomes included long-term mortality, incidence of AKI, and use of renal replacement therapy (RRT). Subgroup and meta-regression analyses were performed to explore heterogeneity.Main results: A total of 25 observational studies comprising 8,165 patients were included. The incidence of AKI in CA survivors was 40.3% (range 32.9-47.8%). In stage 3 AKI, one-fourth of patients required RRT. AKI was associated with an increased risk of both short-term (OR 2.27 [95% CI 1.74-2.96]; p < 0.001) and long-term mortality (OR 1.51 [95% CI 1.93-3.25]; p < 0.001). Meta-regression and subgroup analyses did not suggest any effect of hypothermia on incidence of AKI.Conclusion: AKI complicates the care of 40% of CA survivors and is associated with significantly increased short- and long-term mortality.