#2379 Acute kidney injury as a key predictor of major adverse cardiovascular events in chronic kidney disease patients
Authors: Florens Nans , Aymes Estelle , Gauthier Victoria , Frimat Luc , Laville Maurice , Amouyel Philippe , Nicolas Mansencal , Liabeuf Sophie , Massy Ziad , Stengel Benedicte , de Pinho Natalia Alencar , Hamroun Aghiles 
Published: May 2024

Abstract

Background and Aims
Chronic kidney disease (CKD) significantly raises cardiovascular event risks. The influence of acute-on-chronic kidney incidents is less understood. This study examines the link between acute kidney injury (AKI) episodes and subsequent Major Adverse Cardiovascular Events (MACE) in CKD patients.

Method
From 2013 to 2016, the CKD-REIN cohort enrolled 3033 adults with CKD stages 3-5 (average age 67; 66% male; mean eGFR 33 mL/min/1.73m²) from 40 French outpatient nephrology clinics, reflecting national geographic and legal diversity. During a 5-year follow-up, all AKI episodes, whether inpatient or outpatient, were identified, confirmed, and categorized per KDIGO-AKI standards by an expert panel. Cardiovascular events were evaluated using clinical trial Cardiovascular and Stroke Endpoint Definitions. MACE cumulative incidences (myocardial infarction, stroke, heart failure hospitalization, cardiovascular death) post-AKI were calculated using Aalen-Johansen methods, accounting for kidney failure and death risks. The impact of the first AKI episode on MACE risk was analyzed using a multivariable Cox model, treating AKI as a time-variable and stratifying by characteristics (in/outpatient status, AKI stage, pre-renal causes, renal recovery at discharge). Factors like demographics, cardiovascular risks, CKD severity, and treatments were considered. Interaction and sensitivity analyses were performed, excluding those with prior AKI or cardiovascular disease.

Results
During a median follow-up of 5.2 years, 530 patients experienced an incident AKI episode. The cumulative incidence of MACE at 1 year following this initial episode of AKI was 8.1% [95% confidence interval, 6.1; 10.8], with a median time to occurrence of 6.7 months after AKI. After adjustment for multiple confounders, we observed a substantial increased hazard of MACE associated with a first episode of AKI (HR = 5.99 [4.63; 7.76], p &lt; 0.001), and this association remained significant for each MACE component (Fig. 1A). A dose-response relationship was observed, with higher risks in more severe AKI cases (KDIGO grades 2-3) and among hospitalized versus non-hospitalized patients (Fig. 1B). This association was also observed across all subgroups, without any interaction with age, sex, nor major comorbidities (diabetes, history of AKI, or cardiovascular events), as well as in various sensitivity analyses. Overall, we estimated an attributable risk fraction of 18.1% [13.6; 22.4] for MACE associated with AKI episodes within this population.

Conclusion
Our study highlights a strong dose-response relationship between incident AKI events and the risk of subsequent major cardiovascular events in CKD patients. These findings suggest that AKI may not only be a marker of increased cardiovascular risk but also a potential mediator of this risk. From a clinical perspective, these results underscore the importance of close monitoring and management of AKI in CKD patients to reduce the risk of MACE. This study improves our understanding of the interplay between renal and cardiovascular health, emphasizing the need for integrated care approaches in this high-risk population.