The use of urinary biomarkers to predict acute kidney injury in children after liver transplant

Background AKI after pediatric liver transplantation is associated with increased morbidity and mortality. The role of urinary biomarkers for the prediction of AKI in pediatric patients after liver transplantation has not been previously reported. The primary objective of this prospective pilot study was to determine the predictive capabilities of urinary KIM‐1, NGAL, TIMP‐2, and IGFBP7 for diagnosing AKI. Methods Sixteen children undergoing liver transplantation were enrolled in the study over a 19‐month time period. The Kidney Disease Improving Outcomes criteria for urine output and serum creatinine were used to define AKI. Predictive ability was evaluated using the area under the curve obtained by ROC analysis. Results AKI occurred in 6 (37.5%) of the patients between 2 and 4 days after transplant. There were no differences in any of the biomarkers prior to transplant. When obtained within 6 hours after transplant, the area under the ROC curve for predicting AKI was 0.758 (95% CI: 0.458‐1.00) for KIM‐1, 0.900 (95% CI: 0.724‐1.00) for NGAL, and 0.933 (95% CI: 0.812‐1.00) for the product of TIMP‐2 and IGFBP7 ([TIMP‐2]·[IGFBP7]). Conclusions Our results show that both NGAL and [TIMP‐2]·[IGFBP7] provide significant discrimination for AKI risk following liver transplant in children. Larger studies are needed to determine the optimal time point for measuring these biomarkers and to validate our findings.