Cryptic and Overt Acute Kidney Injury Share Biomarker Characteristics in Pediatric Acute Respiratory Distress Syndrome.

IMPORTANCE: Patients with acute respiratory distress syndrome (ARDS) are at risk for higher morbidity and mortality with concurrent acute kidney injury (AKI). AKI diagnosis relies on serum creatinine, which is confounded by fluid overload. Use of fluid overload-adjusted creatinine can diagnose AKI (termed Cryptic AKI) that would otherwise be missed by the traditional Kidney Disease Improving Global Outcomes (KDIGO) definition. It is unknown whether Cryptic AKI is biochemically distinct from patients without AKI. OBJECTIVES: Determine whether pediatric ARDS patients with Cryptic AKI have a biochemical profile that is similar or distinct from patients with KDIGO-defined AKI or no AKI. DESIGN SETTING AND PARTICIPANTS: Observational study of 333 pediatric ARDS patients in a quaternary PICU. MAIN OUTCOMES AND MEASURES: Mortality, length of stay, and ventilator-free days were measured for all patients. Biomarkers indicative of tissue damage and inflammation were measured on days 1, 3, and 7 of ARDS. RESULTS: Cryptic AKI was associated with higher mortality and longer length of stay than no AKI, similar to KDIGO AKI. Biomarkers angiopoietin-2, pro-collagen III N-terminal peptide, heat shock protein 70, tumor necrosis factor receptor 1, and interleukin-8 were significantly higher in Cryptic and KDIGO AKI than in no AKI. CONCLUSIONS AND RELEVANCE: Cryptic AKI is clinically significant and represents true kidney injury, with a biomarker profile similar to KDIGO AKI and distinct from patients without AKI.