Acute kidney injury in patients with sepsis: a contemporary analysis

To analyze the clinical characteristics of septic acute kidney injury (AKI) according to the Acute Kidney Injury Network (AKIN) classification, and to evaluate the capacity of this system in predicting in-hospital mortality of septic patients.

Patients with sepsis admitted to the infectious diseases intensive care unit (ICU) of our hospital between January 2004 and June 2007 were retrospectively studied. Maximum AKIN stage within the first three days of hospitalization was recorded.

Three hundred fifteen patients were evaluated. According to AKIN criteria, 99 patients (31.4%) had AKI: 26.2% at stage 1, 20.2% at stage 2, and 53.6% at stage 3. Four patients (1.9%) with no AKI progressed to stage 1, two patients (7.7%) at stage 1 progressed to stage 2, one patient (3.8%) at stage 1 progressed to stage 3, and one patient at stage 2 (5%) progressed to stage 3. The mortality rate was 25.3% and increased significantly from normal renal function to stage 3 (normal, 12.5%; stage 1, 34.6%; stage 2, 45%; stage 3, 64.1%; p<0.0001). After adjusting for age, gender, race, pre-existing chronic kidney disease, illness severity as evaluated by acute physiology and chronic health evaluation, version II (APACHE II) score, need for mechanical ventilation, and vasopressor use, AKIN stage 1 (odds ratio (OR) 3.03, 95% confidence interval (CI) 1.12-8.19, p=0.029), stage 2 (OR 3.3, 95% CI 1.11-9.78, p=0.031), and stage 3 (OR 7.35, 95% CI 3.13-17.25, p<0.0001) predicted mortality.

AKIN criteria are a useful tool to characterize and stratify septic patients according to the risk of death.