Landscape of Biomarker Use in Critically Ill Patients: Systematic Evidence Map of Acute Kidney Injury and Implications for Practice

OBJECTIVES: Create systematic evidence maps of novel biomarkers of kidney injury from a mapping review to guide future implementation in patient care. DATA SOURCES: PubMed/MEDLINE and Embase. STUDY SELECTION: Systematic evidence maps included clinical trials and observational studies in critically ill patients, investigating novel kidney biomarkers for acute kidney injury (AKI). DATA EXTRACTION: Six thousand eight hundred five records were screened, and 1116 studies were included that related to one or more novel biomarkers and AKI. DATA SYNTHESIS: Adult populations accounted for 78.6% of the studies, and 93.3% used a cohort design to investigate AKI biomarkers. Mixed critically ill populations, cardiac surgery, and sepsis were identified as the most frequently studied clinical contexts in 69.5% of the studies. Systematic evidence maps were synthesized for biomarker studies to predict AKI (n = 944), prognosticate clinical outcomes (n = 647), diagnose AKI etiology (n = 109), enrich clinical trials (n = 6), and manage AKI (n = 12). Implementation strategies for patient care included surveilling patients at risk of AKI, including patients undergoing surgery and those exposed to multiple nephrotoxic drugs. CONCLUSIONS: Substantial clinical evidence assessing the accuracy of biomarkers compared with diagnosis of AKI exists, with fewer practical trials in clinical use. Still, guidance on implementation approaches can be gleaned from evaluations using biomarkers for the management of critically ill patients, particularly in surgical and nephrotoxin-exposed populations where evidence is available. This review identifies the landscape of current evidence and highlights priorities for future management and enrichment trials needed to bridge the gap between predictive accuracy and clinical decision-making.