Serum KIM-1 and Cystatin Levels as the Predictors of Acute Kidney Injury in Asphyxiated Neonates

Background: Asphyxia may lead to serious complications, among which acute kidney injury (AKI) is the most common. Early diagnosis of AKI can help prevent impaired acid-base, fluid, and electrolyte balance that may lead to life-threatening complications. This study aimed to evaluate the effect of kidney injury molecule-1 (KIM-1) and cystatin-C in the early diagnosis of AKI among asphyxiated neonates. Methods: This case-control study was conducted on 45 asphyxiated neonates, 24 of whom were in the control group and 23 cases were in the case group. Creatinine (Cr), KIM-1, and cystatin-C were measured for participants within 8 h and 4 days after birth and compared between case and control groups. Results: The mean level of Cr-Standardized KIM-1 measured within 8 h and 4 days after birth was significantly higher in the case group, compared to the control group (P-value 0.05). The mean level of Cr-Standardized cysteine, only 4 days after birth, was significantly higher in the case group, compared to the control group (P-value 0.05). A receiver operating characteristic (ROC) curve analysis demonstrated that between the two biomarkers with two measurements, the KIM-1 Cr-Standardized within 4 days had the highest area under the curve (AUC) (0.751, 95% CI: 0.597-0.905). Moreover, the results of ROC curve analysis showed that Cr-Standardized KIM-1 within 4 days after birth with a critical value of 0.67 ng/ml allowed to predict kidney failure in newborns with 57.1‌% sensitivity and 86.4‌% specificity. Conclusion: The findings of the present study show that high-specificity KIM-1 is a good biomarker for the early detection of acute renal failure in asphyxiated infants; however, similar expectations cannot exist with regards to cystatin-C for at least the first 8 h after birth.