Impact of pre-hospital renal function on the detection of acute kidney injury in acute decompensated heart failure

•Pre-hospital renal function levels improve acute kidney injury identification.•Acute kidney injury is already present at admission in a large number of patients.•Worse clinical outcomes are associated with pre-hospital renal function.•Acute kidney injury at admission identifies patients with worse prognosis. Acute kidney injury (AKI) is a serious complication in patients hospitalized for decompensated heart failure (HF). Currently, AKI definitions consider creatinine levels at admission as reference of baseline renal function (RF). However, renal impairment may already be present at admission. We aimed to study the impact on AKI detection of considering outpatient RF as reference. In a cohort of 458 patients hospitalized for decompensated HF, we studied the occurrence of AKI using the standardized KDIGO criteria and grading (stages: 1, 2, 3), and considering two different definitions according to the RF used as reference or baseline: the latest outpatient measurement prior to admission vs. the first measurement at admission. We compared the prevalence, timing and prognostic value for both AKI definitions. The definition based on outpatient RF was associated with an increase in overall AKI detection from 20.1% to 33.8% (p