URINARY biomarkers of renal stress and injury may offer earlier detection of acute kidney injury (AKI) in patients with severe COVID-19, according to findings from a prospective observational study. The investigation evaluated critically ill adults admitted to intensive care between November 2020 and May 2021, analyzing urine samples collected at admission and during the following 48 hours for kidney injury molecule 1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), IL-18, and the cell cycle arrest markers insulin-like growth factor binding protein 7 (IGFBP-7) and tissue inhibitor of metalloproteinases 2 (TIMP-2).
Among the 106 patients studied, 22.6% developed AKI. Those with AKI were older and had higher needs for invasive mechanical ventilation, inotropic support, prolonged hospitalization, and experienced greater mortality compared to patients without AKI. To account for urine dilution and production rate, biomarker concentrations were normalized to urinary creatinine.
Receiver operating characteristic analysis demonstrated that the combined marker TIMP-2 × IGFBP-7 offered the most reliable predictive value. A cut-off greater than 0.301 (ng/ml)²/1,000 achieved 84.1% sensitivity though specificity was limited at 31.6%. After normalization, diagnostic performance improved, with an area under the curve (AUC) of 0.663 and significance at p<0.001. IL-18, KIM-1, and NGAL also demonstrated predictive value with AUCs of 0.653, 0.646, and 0.552, respectively. The results suggest that urinary cell cycle arrest biomarkers, particularly TIMP-2 and IGFBP-7, may be more effective than traditional injury markers in identifying patients at risk of developing AKI in the context of COVID-19. These findings highlight the potential clinical utility of integrating urinary biomarkers into early diagnostic strategies for critically ill patients, though further validation in larger cohorts is warranted. Reference: Samra T et al. Utility of Urinary Biomarkers for Diagnosis of Acute Kidney Injury (AKI) in COVID-19. Indian J Clin Biochem. 2025;40(4):636-643.
