Acute Kidney Injury and Mortality Prognosis in Acute Coronary Syndrome Patients: A Meta-analysis

Aim: The aim of this study is to provide a robust estimate of mortality risk in acute coronary syndrome (ACS)-associated acute kidney injury (AKI) to inform clinical practice and policy.

Methods: A meta-analysis of cohort studies evaluating outcomes of ACS and which reported AKI and AKI-associated mortality. Studies were excluded if they incorporated patients not admitted through the emergency department (i.e. for elective procedures), were limited to cardiogenic shock or cardiac arrest, or relied on registry data for outcomes without further adjudication. The predictor was ACS-associated AKI and outcomes early (30 day or in-hospital) mortality and late-mortality (post-hospital discharge).

Results: Thirty-six studies with 37 unique cohorts comprising 100 476 patients were included. The pooled rate of ACS-associated AKI was 15.8%. In 32 cohorts reporting early mortality, the crude early mortality rate was 15.0% amongst those with AKI compared with 2.0% amongst those without AKI. The pooled estimate of the relative risk of AKI-associated early mortality was 4.1 (95% confidence interval: 3.3 to 5.0) with high heterogeneity between studies (I  = 84% (61% to 88%)). When heterogeneity was accounted for mathematically using credibility ceilings, the risk of mortality was lower, but still clinically significant (3.1 (2.6 to 3.6)). In 19 cohorts reporting late mortality (1 to 10 years), the relative risk of AKI-associated mortality was 2.6 (2.0 to 3.3) with moderate heterogeneity (I  = 65 % [35% to 88%]). Following application of credibility ceiling relative risk estimate dropped to 2.2 (1.9 to 2.6).

Conclusions: Acute coronary syndrome-associated AKI is associated with more than a three-fold increase in early mortality and more than two-fold in long-term mortality.