Abstract
Acute kidney injury (AKI) is a complication of COVID-19 and urinary biomarkers of renal "stress" and "injury" can be utilised for an early diagnosis. In this prospective observational study, critically-ill adult patients with COVID-19 disease from November 2020 to May 2021 were recruited and urine samples collected at the time of admission to ICU, and subsequently at 12, 24 and 48 h and analysed for biomarkers of "renal injury" namely KIM-1, NGAL, IL-18, and cell cycle arrest biomarker IGFBP-7 and TIMP-2 which have been reported to increase following renal stress. Spot urine samples were collected and to adjust for dilution, sample volume and rate of urine production, assays of the biomarkers were normalised by dividing the values with urinary creatinine concentration. The incidence of AKI in our study was 22.64% (24/106). Patients in the AKI group were older with significantly higher requirements for invasive mechanical ventilation, inotropic support, longer hospital stay, and higher mortality. Diagnostic performance of various biomarkers to predict AKI was compared with receiver operator characteristics curve analysis. TIMP-2 × IGFBP7 > 0.301 (ng/ml)(2)/1000 predicted AKI with sensitivity and specificity of 84.1% and 31.6% (AUC = 0.579, and p < 0.035), respectively. AUC was 0.663 with a p-value < 0.001 when cut-off values after normalisation were > 0.87 (ng/mmol)(2)/1000. IL-18, TIM-1, NGAL predicted AKI at cut-off values of 24.936, 12,372.766, and 8017.74 ng/mmol with AUC of 0.653 (p ≤ 0.001), 0.646 (p ≤ 0.001), and 0.552 (p = 0.035), respectively. Urinary cell cycle arrest biomarkers have a more promising role over biomarkers of renal injury in identification of patients at risk of AKI.