Association of a history of acute kidney injury with major adverse cardiovascular events in chronic kidney disease patients

Abstract Background/introduction Acute kidney injury (AKI) is strongly associated with major adverse cardiovascular events (MACE), particularly heart failure, in both general and critically ill populations. A recent study questioned whether this association holds true only for patients without chronic kidney disease (CKD). Purpose To evaluate the association of a history of AKI with MACE in a large real-world CKD population defined using the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Methods A retrospective cohort study was conducted using Merative® Explorys electronic health records (>54 million patients) from Jan 2010 to Dec 2019. Six cohorts of CKD patients (diagnosed or not) were created, one for each stage (1-5). Patients were required to have two consecutive abnormal eGFR, uACR/uPCR results within 3-18 months to determine CKD stage, to have at least a 12-months lookback period, and no history of end-stage kidney disease. CKD classification was not mutually exclusive (individual patients could contribute to multiple stages). Index date was the date of the second abnormal test. History of AKI was defined using ICD diagnosis codes, not through biological changes. We followed each patient until the occurrence of a composite of MACE including death, coronary events [acute coronary syndrome + coronary revascularization], any stroke, hospitalization for heart failure, or loss to follow-up, or for up to 5 years. We used multivariable Cox proportional hazards regression to estimate associations between the history of AKI and the risk of MACE during follow-up, adjusted for the following confounders: age, sex, ethnicity, systolic blood pressure, eGFR, BMI, CV history, diabetes, and any CKD diagnosis at baseline. Results Most of the 969,394 patients included in at least one CKD stage cohort were in stage 3a (see table) and Caucasian. Mean ages were 57-75y and 42%-64% were females across the 5 CKD stages. The prevalence of pre-existing CV disease increased from 24% in stage 1 to 57% in stage 4. The proportion of patients with a history of AKI increased from 4% in stage 1 to 36% in stage 4, as well as, the proportion of patients with a ICD code for CKD diagnosis at baseline (3% to 44%). The 5-year incidence of the composite of MACE increased from 25.1% in stage 1 to 65.8% in stage 5. Death was the most frequent event across all stages. In multivariable analysis, a history of AKI was associated with increased risk of MACE (hazard ratios, HR 1.19 to 1.32), all-cause death (HR 1.12 to 1.86), and hospitalization for Heart Failure (HR 1.59 to 1.98) for all CKD stages, and coronary events for stage 2 to 5 (HR 1.14 to 1.22), but not stroke. Conclusion Patients with CKD and a history of AKI are at higher risk of adverse CV outcomes, especially hospitalization for heart failure. This study suggest that these patients should receive cardio -protective intervention.