Incidence, risk factors and outcome for acute kidney injury in the ICU: a prospective observational study

Aim: To identify the incidence, causes and risk factors of AKI and to evaluate time course and outcome of AKI in ICU patients. Methods: All adult patients admitted to the ICU with a stay of 48 h or more were enrolled in the study. The diagnosis and classification of AKI was performed according to the Kidney Diseases: Improving Global Outcomes (KDIGO) criteria. The follow-up period is limited to 7 days. The primary endpoint of the study was to detect the incidence of AKI. Results: The overall incidence of AKI was 38.5% (n=67). In 88% of patients, AKI occurred within 0-48h. AKI resolved within 48h in 33 patients and within 2 to 7 days in 15 patients after AKI onset, progression to acute kidney disease was observed in 19 patients. AKI patients significantly older than no-AKI patients. The higher rate of mortality and mechanical ventilation was associated with AKI. In logistic regression, higher APACHE II score, pre-existing cardiovascular disease and chronic kidney disease, and vasoactive medications requirement were independent risk factors for AKI. An admission sCr cut-off of 1.125 mg/dL showed excellent discrimination. Discussion: AKI is a frequent and early complication with a high mortality rate in the ICU. The majority of cases were KDIGO stage 1 and resolved quickly. Advanced age, increased APACHE II score, pre-existing CVD and CKD are risk factors for the development of AKI. Admission sCr value may be useful to identify the patients at risk of AKI in the ICU. Clinical trial number and date: NCT05970952 / November 10 2025.