Chronic Kidney Disease and Superimposed Acute Kidney Injury: Greater Impact of Acute Insults on Outcomes.

Introduction: Acute kidney injury (AKI) and chronic kidney disease (CKD) are widely correlated. However, the risk factors associated with outcomes of AKI in CKD patients have not been widely studied to date. Objectives: To identify factors associated with outcomes of death and need for kidney support therapy (KST) in patients with CKD who present with AKI during hospital stay. Methods: Retrospective cohort conducted from July 2018 to June 2022 that included patients with CKD and superimposed AKI. Sociodemographic data related to CKD, AKI, and the progression of patients to outcomes as death and KST were collected. The results were discussed with a significance level of Results: A total of 327 patients were included. The patients had a mean age of 68.6 ± 11.4 years, the majority were men, and the most prevalent comorbidities were hypertension (81.7%) and cardiovascular disease (61.5%). The mean creatinine was 1.85 ± 0.74 mg/dL. The main etiology of CKD was undetermined (26.6%) and of AKI was septic (45.3%). Patients were hospitalized mainly for infectious or cardiovascular causes (22.3% each). Overall mortality was 29.1%, and the need for KST was 35.2%. In the intensive care unit (ICU), 73.2% required dialysis and 74.4% died, reaching 85.7% in those with KST. CKD staging was not associated with any of the primary outcomes. The risk factors for KST were obesity, ATN-ISS score, and creatinine elevation greater than three times the baseline. The risk factors for death were ATN-ISS score, undetermined CKD, septic AKI, ICU admission, and KST. Conclusions: Mortality and need for KST in CKD patients admitted to the ICU and who develop AKI are high. Variables related to AKI were more relevant than those related to CKD for clinical outcomes.