Urinary biomarkers in prediction of subclinical acute kidney injury in pediatric oncology patients treated with nephrotoxic agents.

BACKGROUND: Acute kidney injury (AKI) is a common complication in pediatric oncology patients, most often caused by nephrotoxic drugs. We aimed to assess whether levels of urinary kidney injury molecule-1 (uKIM-1), neutrophil gelatinase-associated lipocalin (uNGAL), liver fatty acid binding protein (uL-FABP) and Vanin-1 (uVNN-1), individually and in combination-integrated could be early markers for cytotoxic treatment induced AKI. METHODS: Children with different malignant diseases treated with cisplatin (CIS) or ifosfamide (IFO) were included. AKI was defined using pediatric KDIGO (Kidney Disease Improving Global Outcomes) criteria by comparing pretreatment serum creatinine (sCr) values with those acquired at 48 h after the first or second chemotherapy cycle. Five serum (at baseline, 2, 6, 24 and 48 h after treatment) and four urine samples (at baseline, 2, 6 and 24 h after treatment) were obtained. Urinary biomarkers (uBm) were normalized to urine creatinine. RESULTS: Thirty-eight patients were assessed. Within 48 h following chemotherapy 6 (15.79%) patients experienced AKI. Patients with AKI were younger and tend to have lower baseline sCr values than patients without AKI, but these differences were not statistically significant. Compared to baselines, all uBm were significantly increased during the first 6 h while sCr concentrations did not change significantly during the study period. The median increases in uBm during the first 6 h after treatment were 529.8% (interquartile range - IQR, 63.9-1835.2%) - 2194.0% (IQR, 255.3-4695.5%) in AKI vs. 302.2% (IQR 114.6-561.2%) -429.8% (156.5-1467.0%) in non-AKI group depending of tested uBm. The magnitude of these changes over time didn't differ significantly between groups. The area under receiver operator curve (AUC) for uL-FABP and uNGAL at 24 h after chemotherapy were 0.81 and 0.72, respectively. The ROC analysis revealed that the other individual biomarkers' performance at any time-point wasn't statistically significant (AUC < 0.7). A model of integrated-combined uBm, 2 h (AUC 0.78), 6 h (AUC 0.85) and 24 h after (AUC 0.92) treatment with CIS and/or IFO showed good utility for early AKI prediction. CONCLUSIONS: The results of this study support that the use of the uBm to improves early AKI prediction in patients receiving CIS and/or IFO containing chemotherapy. Further studies on larger comparable groups of patients are needed.