Acute kidney injury-epidemiology in intensive care unit patients 2: study protocol for a prospective international multicentre cohort study

Introduction: Reports on the epidemiology and outcomes of acute kidney injury in the critically ill provide variable estimates based on differences in populations and underlying exposures. Current and generalisable incidence data are needed along with information on long-term patient and kidney outcomes.The acute kidney injury-epidemiology in intensive care unit patients 2 (AKI-EPI 2) study aims to describe the occurrence and associated outcomes of AKI in critically ill patients worldwide. In addition, in selected centres, it aims to further describe the influence of AKI on long-term kidney and patient outcomes. Methods and analysis: This is an international prospective, observational study of patients admitted to the intensive care unit (ICU). Each participating centre will record data from 100 consecutive patients fulfilling the following eligibility criteria: age≥18 years, admission to the ICU for more than 24 hours and informed consent according to the local ethics committee (EC). Exclusion criteria include end-stage kidney disease treated with maintenance renal replacement therapy (RRT), readmission to the ICU or missing AKI-defining data. Particular attention will be paid to recruiting centres from all continents and to ensure geographical diversity and representativeness. The target sample is 10 642 patients. The primary endpoint is the occurrence and maximum severity of AKI within 7 days of ICU admission according to 2012 Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Secondary endpoints include AKI severity, AKI duration, RRT use and hospital survival. In selected centres, health-related quality of life, major adverse kidney events and vital status will also be captured at day 90 and 1 year from admission. Ethics and dissemination: AKI-EPI 2 has been approved by the EC of the Ghent University and University Hospital. Approval will be sought by corresponding ECs for all participating centres.Results will be presented at conferences, disseminated in peer-reviewed journals and will guide future research in the field of critical care nephrology. Trial registration: NCT07207031.