Acute kidney disease after acute kidney injury: incidence, risk factors, and association with de novo chronic kidney disease

Acute Kidney Disease (AKD) is defined as acute kidney injury (AKI) persisting for 7 to 90 days and represents a window for interventions to improve renal outcomes. However, data on AKD remain underexplored. This retrospective cohort study at Tongji Hospital, China, included 23,868 adult patients who survived at least one AKI episode between January 2015 and April 2024. Using electronic medical record data, we aimed to quantify the incidence of AKD among AKI survivors, identify independent risk factors, and evaluate the association between AKD and de novo chronic kidney disease (CKD). Among the cohort, 10,884 patients (45.6%) progressed to AKD. Multivariable logistic regression revealed that advanced age, preexisting hypertension, heart failure, cirrhosis, recent diuretic use, hepatorenal syndrome, higher baseline estimated glomerular filtration rate, higher AKI stage, and dialysis-requiring AKI were independent risk factors for AKD. Fine-Gray competing-risk analysis accounting for acute-phase mortality confirmed that higher AKI severity was independently associated with AKD progression. In a subcohort of 6597 patients without preexisting CKD who had at least one year of follow-up, 19.8% developed de novo CKD. Cox proportional hazards analysis demonstrated that patients with AKD had a significantly increased risk of de novo CKD compared to those without AKD (HR 1.92, 95% CI 1.70-2.17). These findings highlight the high proportion of AKD among patients with AKI, and emphasize the importance of early detection and targeted management for high-risk groups. It is critical to strengthen post-discharge renal function monitoring and intervention strategies for AKI patients to improve long-term renal outcomes.