Urinary biomarkers predict progression and adverse outcomes ofacute kidney injury in critical illness.

Background Acute Kidney Injury (AKI) is common in hospitalized patients and is associated with high morbidity and mortality. The Dublin Acute Biomarker Group Evaluation (DAMAGE) Study is a prospective cohort study of critically ill patients (n = 717). We hypothesised that novel urinary biomarkers would predict progression of AKI and associated outcomes. Methods The primary (diagnostic) analysis assessed the ability of biomarkers levels at the time of early Stage 1 or2 AKI to predict progression to higher AKI Stage, RRT or Death within 7 days of ICU admission. In the secondary (prognostic) analysis, we investigated the association between biomarker levels and RRT or Death within 30 days. Results In total, 186 patients had an AKI within 7 days of admission. In the primary (diagnostic) analysis, eight of the 14 biomarkers were independently associated with progression. The best predictors were Cystatin C (aOR 5.2; 95% CI, 1.3-23.6), IL-18 (aOR 5.1; 95% CI, 1.8-15.7), Albumin (aOR 4.9; 95% CI, 1.5-18.3) and NGAL (aOR 4.6; 95% CI, 1.4-17.9). ROC and Net Reclassification Index analyses similarly demonstrated improved prediction by these biomarkers. In the secondary (prognostic) analysis of Stage 1-3 AKI cases, IL-18, NGAL, Albumin, and MCP-1 were also independently associated with RRT or Death within 30 days. Conclusions Among 14 novel urinary biomarkers assessed, Cystatin C, IL-18, Albumin and NGAL were the best predictors of Stage 1-2 AKI progression. These biomarkers, after further validation, may have utility to inform diagnostic and prognostic assessment and guide management of AKI in critically ill patients.