Background: Acute kidney injury (AKI) has a high global incidence with observable complications in critically ill patients. Long-term disease and medication complexity contribute to devastating chronic kidney disease (CKD) and diminish quality of life. Establishing new biomarkers would guide patient care and facilitate novel therapeutics development.
Methods: Serum and urinary levels of creatinine, CysC, and NGAL were estimated in 86 renal patients and compared with healthy controls for AKI and CKD categorization. Creatinine and CysC measurements were used to estimate GFR. Biopsy tissues were prepared for light microscopy for further characterization. Patients’ demographic data were used in group association study.
Results: Thirty-six patients met the criteria for AKI and 50 for CKD. Mean values of serum Cystatin C (CysC) were higher than controls but similar in both disease states, while urine levels were slightly high in CKD patients and remained steady by the end of follow-up (EF-Up). Further, a 2.7-fold and 5.5-fold increase in serum NGAL were observed in AKI and CKD, respectively, and a dramatic 7.0-fold reduction in AKI group at EF-Up. Similarly, urine NGAL for AKI and CKD increased 3-fold and 6-fold respectively on admission, which multiplied to 7.3-fold and 10.7-fold at EF-Up. ROC assessment curve revealed a relatively higher NGAL performance at good predictive values than CysC (p< 0.009).
Conclusion: We showed a higher urine NGAL and CysC sensitivity and specificity than their serum counterparts, providing a powerful discriminative tool between AKI and CKD. CysC, however, displayed less sensitive performance than NGAL, indicating effects by enigmatic non-specific factors.